layout/base/nsCSSFrameConstructor.cpp
author Ryan VanderMeulen <ryanvm@gmail.com>
Mon, 29 Jul 2013 15:19:34 -0400
changeset 152713 a59ad3157c17f3df0a132979f428c65211e4ce23
parent 152689 27a5c8dd5ff757042366bd15904fcccda074dd96
child 152873 552bca1bc885acca25c1c431e39a872b6f703b24
permissions -rw-r--r--
Backed out 6 changesets (bug 827713) for reftest failures. Backed out changeset 014cc3de08fb (bug 827713) Backed out changeset 4113172193aa (bug 827713) Backed out changeset 27a5c8dd5ff7 (bug 827713) Backed out changeset 6448c7e05f11 (bug 827713) Backed out changeset b67a72618c66 (bug 827713) Backed out changeset 1279664e0d41 (bug 827713)

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
// vim:cindent:ts=2:et:sw=2:
/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

/*
 * construction of a frame tree that is nearly isomorphic to the content
 * tree and updating of that tree in response to dynamic changes
 */

#include "nsCSSFrameConstructor.h"

#include "mozilla/AutoRestore.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/dom/HTMLSelectElement.h"
#include "mozilla/Likely.h"
#include "mozilla/LinkedList.h"
#include "nsAbsoluteContainingBlock.h"
#include "nsCRT.h"
#include "nsIAtom.h"
#include "nsIURL.h"
#include "nsIHTMLDocument.h"
#include "nsIStyleRule.h"
#include "nsIFrame.h"
#include "nsGkAtoms.h"
#include "nsPresContext.h"
#include "nsILinkHandler.h"
#include "nsIDocument.h"
#include "nsTableFrame.h"
#include "nsTableColGroupFrame.h"
#include "nsTableColFrame.h"
#include "nsIDOMHTMLDocument.h"
#include "nsHTMLParts.h"
#include "nsIPresShell.h"
#include "nsUnicharUtils.h"
#include "nsStyleSet.h"
#include "nsViewManager.h"
#include "nsEventStates.h"
#include "nsStyleConsts.h"
#include "nsTableOuterFrame.h"
#include "nsIDOMXULElement.h"
#include "nsContainerFrame.h"
#include "nsINameSpaceManager.h"
#include "nsIDOMHTMLLegendElement.h"
#include "nsIComboboxControlFrame.h"
#include "nsIListControlFrame.h"
#include "nsISelectControlFrame.h"
#include "nsIDOMCharacterData.h"
#include "nsIDOMHTMLImageElement.h"
#include "nsPlaceholderFrame.h"
#include "nsTableRowGroupFrame.h"
#include "nsIFormControl.h"
#include "nsCSSAnonBoxes.h"
#include "nsTextFragment.h"
#include "nsIAnonymousContentCreator.h"
#include "nsLegendFrame.h"
#include "nsIContentIterator.h"
#include "nsBoxLayoutState.h"
#include "nsBindingManager.h"
#include "nsXBLBinding.h"
#include "nsITheme.h"
#include "nsContentCID.h"
#include "nsContentUtils.h"
#include "nsIScriptError.h"
#include "nsIDocShell.h"
#include "nsIDocShellTreeItem.h"
#include "nsObjectFrame.h"
#include "nsRuleNode.h"
#include "nsIDOMMutationEvent.h"
#include "ChildIterator.h"
#include "nsCSSRendering.h"
#include "nsError.h"
#include "nsLayoutUtils.h"
#include "nsAutoPtr.h"
#include "nsBoxFrame.h"
#include "nsBoxLayout.h"
#include "nsFlexContainerFrame.h"
#include "nsImageFrame.h"
#include "nsIObjectLoadingContent.h"
#include "nsIPrincipal.h"
#include "nsBox.h"
#include "nsTArray.h"
#include "nsGenericDOMDataNode.h"
#include "mozilla/dom/Element.h"
#include "FrameLayerBuilder.h"
#include "nsAutoLayoutPhase.h"
#include "nsCSSRenderingBorders.h"
#include "nsRenderingContext.h"
#include "nsStyleStructInlines.h"
#include "nsViewportFrame.h"
#include "nsPageContentFrame.h"
#include <algorithm>

#ifdef MOZ_XUL
#include "nsIRootBox.h"
#include "nsIDOMXULCommandDispatcher.h"
#include "nsIDOMXULDocument.h"
#include "nsIXULDocument.h"
#endif
#ifdef ACCESSIBILITY
#include "nsAccessibilityService.h"
#endif

#include "nsInlineFrame.h"
#include "nsBlockFrame.h"

#include "nsIScrollableFrame.h"

#include "nsXBLService.h"

#undef NOISY_FIRST_LETTER

#include "nsMathMLParts.h"
#include "mozilla/dom/SVGTests.h"
#include "nsSVGEffects.h"
#include "nsSVGTextFrame2.h"
#include "nsSVGTextPathFrame.h"
#include "nsSVGUtils.h"

#include "nsRefreshDriver.h"
#include "nsRuleProcessorData.h"
#include "GeckoProfiler.h"
#include "nsTextNode.h"

using namespace mozilla;
using namespace mozilla::dom;

// An alias for convenience.
static const nsIFrame::ChildListID kPrincipalList = nsIFrame::kPrincipalList;

nsIFrame*
NS_NewHTMLCanvasFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewHTMLVideoFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

#include "nsSVGTextContainerFrame.h"

nsIFrame*
NS_NewSVGOuterSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGOuterSVGAnonChildFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGInnerSVGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGPathGeometryFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGGFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGGenericContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGForeignObjectFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGAFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGGlyphFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGTextFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGTextFrame2(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGTSpanFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGUseFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGViewFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
extern nsIFrame*
NS_NewSVGLinearGradientFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
extern nsIFrame*
NS_NewSVGRadialGradientFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
extern nsIFrame*
NS_NewSVGStopFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGMarkerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
extern nsIFrame*
NS_NewSVGImageFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGClipPathFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGTextPathFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGFilterFrame(nsIPresShell *aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGPatternFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGMaskFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGFEContainerFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGFELeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGFEImageFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewSVGFEUnstyledLeafFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);

#include "nsIScrollable.h"
#include "nsINodeInfo.h"
#include "prenv.h"
#include "nsWidgetsCID.h"
#include "nsNodeInfoManager.h"
#include "nsContentCreatorFunctions.h"
#include "nsIServiceManager.h"

#ifdef DEBUG
// Set the environment variable GECKO_FRAMECTOR_DEBUG_FLAGS to one or
// more of the following flags (comma separated) for handy debug
// output.
static bool gNoisyContentUpdates = false;
static bool gReallyNoisyContentUpdates = false;
static bool gNoisyInlineConstruction = false;

struct FrameCtorDebugFlags {
  const char* name;
  bool* on;
};

static FrameCtorDebugFlags gFlags[] = {
  { "content-updates",              &gNoisyContentUpdates },
  { "really-noisy-content-updates", &gReallyNoisyContentUpdates },
  { "noisy-inline",                 &gNoisyInlineConstruction }
};

#define NUM_DEBUG_FLAGS (sizeof(gFlags) / sizeof(gFlags[0]))
#endif


#ifdef MOZ_XUL
#include "nsMenuFrame.h"
#include "nsMenuPopupFrame.h"
#include "nsPopupSetFrame.h"
#include "nsTreeColFrame.h"
#include "nsIBoxObject.h"
#include "nsPIListBoxObject.h"
#include "nsListBoxBodyFrame.h"
#include "nsListItemFrame.h"
#include "nsXULLabelFrame.h"

//------------------------------------------------------------------

nsIFrame*
NS_NewAutoRepeatBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewRootBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewDocElementBoxFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewThumbFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewDeckFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewLeafBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewStackFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewProgressMeterFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewRangeFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewImageBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewTextBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewGroupBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewButtonBoxFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewSplitterFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewMenuPopupFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewPopupSetFrame(nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewMenuFrame (nsIPresShell* aPresShell, nsStyleContext* aContext, uint32_t aFlags);

nsIFrame*
NS_NewMenuBarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewTreeBodyFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

// grid
nsresult
NS_NewGridLayout2 ( nsIPresShell* aPresShell, nsBoxLayout** aNewLayout );
nsIFrame*
NS_NewGridRowLeafFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);
nsIFrame*
NS_NewGridRowGroupFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

// end grid

nsIFrame*
NS_NewTitleBarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewResizerFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);


#endif

nsIFrame*
NS_NewHTMLScrollFrame (nsIPresShell* aPresShell, nsStyleContext* aContext, bool aIsRoot);

nsIFrame*
NS_NewXULScrollFrame (nsIPresShell* aPresShell, nsStyleContext* aContext,
                      bool aIsRoot, bool aClipAllDescendants);

nsIFrame*
NS_NewSliderFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewScrollbarFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);

nsIFrame*
NS_NewScrollbarButtonFrame (nsIPresShell* aPresShell, nsStyleContext* aContext);


#ifdef NOISY_FINDFRAME
static int32_t FFWC_totalCount=0;
static int32_t FFWC_doLoop=0;
static int32_t FFWC_doSibling=0;
static int32_t FFWC_recursions=0;
static int32_t FFWC_nextInFlows=0;
#endif

// Returns true if aFrame is an anonymous flex item
static inline bool
IsAnonymousFlexItem(const nsIFrame* aFrame)
{
  const nsIAtom* pseudoType = aFrame->StyleContext()->GetPseudo();
  return pseudoType == nsCSSAnonBoxes::anonymousFlexItem;
}

static inline nsIFrame*
GetFieldSetBlockFrame(nsIFrame* aFieldsetFrame)
{
  // Depends on the fieldset child frame order - see ConstructFieldSetFrame() below.
  nsIFrame* firstChild = aFieldsetFrame->GetFirstPrincipalChild();
  return firstChild && firstChild->GetNextSibling() ? firstChild->GetNextSibling() : firstChild;
}

#define FCDATA_DECL(_flags, _func)                          \
  { _flags, { (FrameCreationFunc)_func }, nullptr, nullptr }
#define FCDATA_WITH_WRAPPING_BLOCK(_flags, _func, _anon_box)  \
  { _flags | FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS,        \
      { (FrameCreationFunc)_func }, nullptr, &_anon_box }

//----------------------------------------------------------------------

/**
 * True if aFrame is an actual inline frame in the sense of non-replaced
 * display:inline CSS boxes.  In other words, it can be affected by {ib}
 * splitting and can contain first-letter frames.  Basically, this is either an
 * inline frame (positioned or otherwise) or an line frame (this last because
 * it can contain first-letter and because inserting blocks in the middle of it
 * needs to terminate it).
 */
static bool
IsInlineFrame(const nsIFrame* aFrame)
{
  return aFrame->IsFrameOfType(nsIFrame::eLineParticipant);
}

/**
 * True if aFrame is an instance of an SVG frame class or is an inline/block
 * frame being used for SVG text.
 */
static bool
IsFrameForSVG(const nsIFrame* aFrame)
{
  return aFrame->IsFrameOfType(nsIFrame::eSVG) ||
         aFrame->IsSVGText();
}

/**
 * Returns true iff aFrame explicitly prevents its descendants from floating
 * (at least, down to the level of descendants which themselves are
 * float-containing blocks -- those will manage the floating status of any
 * lower-level descendents inside them, of course).
 */
static bool
ShouldSuppressFloatingOfDescendants(nsIFrame* aFrame)
{
  return aFrame->IsFrameOfType(nsIFrame::eMathML) ||
    aFrame->IsBoxFrame() ||
    aFrame->GetType() == nsGkAtoms::flexContainerFrame;
}

/**
 * If any children require a block parent, return the first such child.
 * Otherwise return null.
 */
static nsIContent*
AnyKidsNeedBlockParent(nsIFrame *aFrameList)
{
  for (nsIFrame *k = aFrameList; k; k = k->GetNextSibling()) {
    // Line participants, such as text and inline frames, can't be
    // directly inside a XUL box; they must be wrapped in an
    // intermediate block.
    if (k->IsFrameOfType(nsIFrame::eLineParticipant)) {
      return k->GetContent();
    }
  }
  return nullptr;
}

// Reparent a frame into a wrapper frame that is a child of its old parent.
static void
ReparentFrame(RestyleManager* aRestyleManager,
              nsIFrame* aNewParentFrame,
              nsIFrame* aFrame)
{
  aFrame->SetParent(aNewParentFrame);
  aRestyleManager->ReparentStyleContext(aFrame);
}

static void
ReparentFrames(nsCSSFrameConstructor* aFrameConstructor,
               nsIFrame* aNewParentFrame,
               const nsFrameList& aFrameList)
{
  RestyleManager* restyleManager = aFrameConstructor->RestyleManager();
  for (nsFrameList::Enumerator e(aFrameList); !e.AtEnd(); e.Next()) {
    ReparentFrame(restyleManager, aNewParentFrame, e.get());
  }
}

//----------------------------------------------------------------------
//
// When inline frames get weird and have block frames in them, we
// annotate them to help us respond to incremental content changes
// more easily.

static inline bool
IsFrameSpecial(nsIFrame* aFrame)
{
  return (aFrame->GetStateBits() & NS_FRAME_IS_SPECIAL) != 0;
}

static nsIFrame* GetSpecialSibling(nsIFrame* aFrame)
{
  NS_PRECONDITION(IsFrameSpecial(aFrame), "Shouldn't call this");

  // We only store the "special sibling" annotation with the first
  // frame in the continuation chain. Walk back to find that frame now.
  return static_cast<nsIFrame*>
    (aFrame->GetFirstContinuation()->
       Properties().Get(nsIFrame::IBSplitSpecialSibling()));
}

static nsIFrame* GetSpecialPrevSibling(nsIFrame* aFrame)
{
  NS_PRECONDITION(IsFrameSpecial(aFrame), "Shouldn't call this");
  
  // We only store the "special sibling" annotation with the first
  // frame in the continuation chain. Walk back to find that frame now.  
  return static_cast<nsIFrame*>
    (aFrame->GetFirstContinuation()->
       Properties().Get(nsIFrame::IBSplitSpecialPrevSibling()));
}

static nsIFrame*
GetLastSpecialSibling(nsIFrame* aFrame, bool aReturnEmptyTrailingInline)
{
  for (nsIFrame *frame = aFrame, *next; ; frame = next) {
    next = GetSpecialSibling(frame);
    if (!next ||
        (!aReturnEmptyTrailingInline && !next->GetFirstPrincipalChild() &&
         !GetSpecialSibling(next))) {
      NS_ASSERTION(!next || !frame->IsInlineOutside(),
                   "Should have a block here!");
      return frame;
    }
  }
  NS_NOTREACHED("unreachable code");
  return nullptr;
}

static void
SetFrameIsSpecial(nsIFrame* aFrame, nsIFrame* aSpecialSibling)
{
  NS_PRECONDITION(aFrame, "bad args!");

  // We should be the only continuation
  NS_ASSERTION(!aFrame->GetPrevContinuation(),
               "assigning special sibling to other than first continuation!");
  NS_ASSERTION(!aFrame->GetNextContinuation() ||
               IsFrameSpecial(aFrame->GetNextContinuation()),
               "should have no non-special continuations here");

  // Mark the frame as "special".
  aFrame->AddStateBits(NS_FRAME_IS_SPECIAL);

  if (aSpecialSibling) {
    NS_ASSERTION(!aSpecialSibling->GetPrevContinuation(),
                 "assigning something other than the first continuation as the "
                 "special sibling");

    // Store the "special sibling" (if we were given one) with the
    // first frame in the flow.
    FramePropertyTable* props = aFrame->PresContext()->PropertyTable();
    props->Set(aFrame, nsIFrame::IBSplitSpecialSibling(), aSpecialSibling);
    props->Set(aSpecialSibling, nsIFrame::IBSplitSpecialPrevSibling(), aFrame);
  }
}

static nsIFrame*
GetIBContainingBlockFor(nsIFrame* aFrame)
{
  NS_PRECONDITION(IsFrameSpecial(aFrame),
                  "GetIBContainingBlockFor() should only be called on known IB frames");

  // Get the first "normal" ancestor of the target frame.
  nsIFrame* parentFrame;
  do {
    parentFrame = aFrame->GetParent();

    if (! parentFrame) {
      NS_ERROR("no unsplit block frame in IB hierarchy");
      return aFrame;
    }

    // Note that we ignore non-special frames which have a pseudo on their
    // style context -- they're not the frames we're looking for!  In
    // particular, they may be hiding a real parent that _is_ special.
    if (!IsFrameSpecial(parentFrame) &&
        !parentFrame->StyleContext()->GetPseudo())
      break;

    aFrame = parentFrame;
  } while (1);
 
  // post-conditions
  NS_ASSERTION(parentFrame, "no normal ancestor found for special frame in GetIBContainingBlockFor");
  NS_ASSERTION(parentFrame != aFrame, "parentFrame is actually the child frame - bogus reslt");

  return parentFrame;
}

//----------------------------------------------------------------------

// Block/inline frame construction logic. We maintain a few invariants here:
//
// 1. Block frames contain block and inline frames.
//
// 2. Inline frames only contain inline frames. If an inline parent has a block
// child then the block child is migrated upward until it lands in a block
// parent (the inline frames containing block is where it will end up).

// After this function returns, aLink is pointing to the first link at or
// after its starting position for which the next frame is a block.  If there
// is no such link, it points to the end of the list.
static void
FindFirstBlock(nsFrameList::FrameLinkEnumerator& aLink)
{
  for ( ; !aLink.AtEnd(); aLink.Next()) {
    if (!aLink.NextFrame()->IsInlineOutside()) {
      return;
    }
  }
}

// This function returns a frame link enumerator pointing to the first link in
// the list for which the next frame is not block.  If there is no such link,
// it points to the end of the list.
static nsFrameList::FrameLinkEnumerator
FindFirstNonBlock(const nsFrameList& aList)
{
  nsFrameList::FrameLinkEnumerator link(aList);
  for (; !link.AtEnd(); link.Next()) {
    if (link.NextFrame()->IsInlineOutside()) {
      break;
    }
  }
  return link;
}

inline void
SetInitialSingleChild(nsIFrame* aParent, nsIFrame* aFrame)
{
  NS_PRECONDITION(!aFrame->GetNextSibling(), "Should be using a frame list");
  nsFrameList temp(aFrame, aFrame);
  aParent->SetInitialChildList(kPrincipalList, temp);
}

// -----------------------------------------------------------

// Structure used when constructing formatting object trees.
struct nsFrameItems : public nsFrameList
{
  // Appends the frame to the end of the list
  void AddChild(nsIFrame* aChild);
};

void 
nsFrameItems::AddChild(nsIFrame* aChild)
{
  NS_PRECONDITION(aChild, "nsFrameItems::AddChild");

  // It'd be really nice if we could just AppendFrames(kPrincipalList, aChild) here,
  // but some of our callers put frames that have different
  // parents (caption, I'm looking at you) on the same framelist, and
  // nsFrameList asserts if you try to do that.
  if (IsEmpty()) {
    SetFrames(aChild);
  }
  else {
    NS_ASSERTION(aChild != mLastChild,
                 "Same frame being added to frame list twice?");
    mLastChild->SetNextSibling(aChild);
    mLastChild = nsLayoutUtils::GetLastSibling(aChild);
  }
}

// -----------------------------------------------------------

// Structure used when constructing formatting object trees. Contains
// state information needed for absolutely positioned elements
struct nsAbsoluteItems : nsFrameItems {
  // containing block for absolutely positioned elements
  nsIFrame* containingBlock;
  
  nsAbsoluteItems(nsIFrame* aContainingBlock);
#ifdef DEBUG
  // XXXbz Does this need a debug-only assignment operator that nulls out the
  // childList in the nsAbsoluteItems we're copying?  Introducing a difference
  // between debug and non-debug behavior seems bad, so I guess not...
  ~nsAbsoluteItems() {
    NS_ASSERTION(!FirstChild(),
                 "Dangling child list.  Someone forgot to insert it?");
  }
#endif
  
  // Appends the frame to the end of the list
  void AddChild(nsIFrame* aChild);
};

nsAbsoluteItems::nsAbsoluteItems(nsIFrame* aContainingBlock)
  : containingBlock(aContainingBlock)
{
}

// Additional behavior is that it sets the frame's NS_FRAME_OUT_OF_FLOW flag
void
nsAbsoluteItems::AddChild(nsIFrame* aChild)
{
  NS_ASSERTION(aChild->PresContext()->FrameManager()->
               GetPlaceholderFrameFor(aChild),
               "Child without placeholder being added to nsAbsoluteItems?");
  aChild->AddStateBits(NS_FRAME_OUT_OF_FLOW);
  nsFrameItems::AddChild(aChild);
}

// -----------------------------------------------------------

// Structure for saving the existing state when pushing/poping containing
// blocks. The destructor restores the state to its previous state
class MOZ_STACK_CLASS nsFrameConstructorSaveState {
public:
  typedef nsIFrame::ChildListID ChildListID;
  nsFrameConstructorSaveState();
  ~nsFrameConstructorSaveState();

private:
  nsAbsoluteItems* mItems;      // pointer to struct whose data we save/restore
  nsAbsoluteItems  mSavedItems; // copy of original data

  // The name of the child list in which our frames would belong
  ChildListID mChildListID;
  nsFrameConstructorState* mState;

  // State used only when we're saving the abs-pos state for a transformed
  // element.
  nsAbsoluteItems mSavedFixedItems;

  bool mSavedFixedPosIsAbsPos;

  friend class nsFrameConstructorState;
};

// Structure used to keep track of a list of bindings we need to call
// AddToAttachedQueue on.  These should be in post-order depth-first
// flattened tree traversal order.
struct PendingBinding : public LinkedListElement<PendingBinding>
{
#ifdef NS_BUILD_REFCNT_LOGGING
  PendingBinding() {
    MOZ_COUNT_CTOR(PendingBinding);
  }
  ~PendingBinding() {
    MOZ_COUNT_DTOR(PendingBinding);
  }
#endif

  nsRefPtr<nsXBLBinding> mBinding;
};

// Structure used for maintaining state information during the
// frame construction process
class MOZ_STACK_CLASS nsFrameConstructorState {
public:
  typedef nsIFrame::ChildListID ChildListID;

  nsPresContext            *mPresContext;
  nsIPresShell             *mPresShell;
  nsFrameManager           *mFrameManager;

#ifdef MOZ_XUL
  // Frames destined for the kPopupList.
  nsAbsoluteItems           mPopupItems;
#endif

  // Containing block information for out-of-flow frames.
  nsAbsoluteItems           mFixedItems;
  nsAbsoluteItems           mAbsoluteItems;
  nsAbsoluteItems           mFloatedItems;

  nsCOMPtr<nsILayoutHistoryState> mFrameState;
  // These bits will be added to the state bits of any frame we construct
  // using this state.
  nsFrameState              mAdditionalStateBits;

  // When working with the -moz-transform property, we want to hook
  // the abs-pos and fixed-pos lists together, since transformed
  // elements are fixed-pos containing blocks.  This flag determines
  // whether or not we want to wire the fixed-pos and abs-pos lists
  // together.
  bool                      mFixedPosIsAbsPos;

  // A boolean to indicate whether we have a "pending" popupgroup.  That is, we
  // have already created the FrameConstructionItem for the root popupgroup but
  // we have not yet created the relevant frame.
  bool                      mHavePendingPopupgroup;

  // If false (which is the default) then call SetPrimaryFrame() as needed
  // during frame construction.  If true, don't make any SetPrimaryFrame()
  // calls, except for generated content which doesn't have a primary frame
  // yet.  The mCreatingExtraFrames == true mode is meant to be used for
  // construction of random "extra" frames for elements via normal frame
  // construction APIs (e.g. replication of things across pages in paginated
  // mode).
  bool                      mCreatingExtraFrames;

  nsCOMArray<nsIContent>    mGeneratedTextNodesWithInitializer;

  TreeMatchContext          mTreeMatchContext;

  // Constructor
  // Use the passed-in history state.
  nsFrameConstructorState(nsIPresShell*          aPresShell,
                          nsIFrame*              aFixedContainingBlock,
                          nsIFrame*              aAbsoluteContainingBlock,
                          nsIFrame*              aFloatContainingBlock,
                          nsILayoutHistoryState* aHistoryState);
  // Get the history state from the pres context's pres shell.
  nsFrameConstructorState(nsIPresShell*          aPresShell,
                          nsIFrame*              aFixedContainingBlock,
                          nsIFrame*              aAbsoluteContainingBlock,
                          nsIFrame*              aFloatContainingBlock);

  ~nsFrameConstructorState();
  
  // Function to push the existing absolute containing block state and
  // create a new scope. Code that uses this function should get matching
  // logic in GetAbsoluteContainingBlock.
  // Also makes aNewAbsoluteContainingBlock the containing block for
  // fixed-pos elements if necessary.
  // aPositionedFrame is the frame whose style actually makes
  // aNewAbsoluteContainingBlock a containing block. E.g. for a scrollable element
  // aPositionedFrame is the element's primary frame and
  // aNewAbsoluteContainingBlock is the scrolled frame.
  void PushAbsoluteContainingBlock(nsIFrame* aNewAbsoluteContainingBlock,
                                   nsIFrame* aPositionedFrame,
                                   nsFrameConstructorSaveState& aSaveState);

  // Function to push the existing float containing block state and
  // create a new scope. Code that uses this function should get matching
  // logic in GetFloatContainingBlock.
  // Pushing a null float containing block forbids any frames from being
  // floated until a new float containing block is pushed.
  // XXX we should get rid of null float containing blocks and teach the
  // various frame classes to deal with floats instead.
  void PushFloatContainingBlock(nsIFrame* aNewFloatContainingBlock,
                                nsFrameConstructorSaveState& aSaveState);

  // Function to return the proper geometric parent for a frame with display
  // struct given by aStyleDisplay and parent's frame given by
  // aContentParentFrame.
  nsIFrame* GetGeometricParent(const nsStyleDisplay* aStyleDisplay,
                               nsIFrame* aContentParentFrame) const;

  /**
   * Function to add a new frame to the right frame list.  This MUST be called
   * on frames before their children have been processed if the frames might
   * conceivably be out-of-flow; otherwise cleanup in error cases won't work
   * right.  Also, this MUST be called on frames after they have been
   * initialized.
   * @param aNewFrame the frame to add
   * @param aFrameItems the list to add in-flow frames to
   * @param aContent the content pointer for aNewFrame
   * @param aStyleContext the style context resolved for aContent
   * @param aParentFrame the parent frame for the content if it were in-flow
   * @param aCanBePositioned pass false if the frame isn't allowed to be
   *        positioned
   * @param aCanBeFloated pass false if the frame isn't allowed to be
   *        floated
   * @param aIsOutOfFlowPopup pass true if the frame is an out-of-flow popup
   *        (XUL-only)
   */
  void AddChild(nsIFrame* aNewFrame,
                nsFrameItems& aFrameItems,
                nsIContent* aContent,
                nsStyleContext* aStyleContext,
                nsIFrame* aParentFrame,
                bool aCanBePositioned = true,
                bool aCanBeFloated = true,
                bool aIsOutOfFlowPopup = false,
                bool aInsertAfter = false,
                nsIFrame* aInsertAfterFrame = nullptr);

  /**
   * Function to return the fixed-pos element list.  Normally this will just hand back the
   * fixed-pos element list, but in case we're dealing with a transformed element that's
   * acting as an abs-pos and fixed-pos container, we'll hand back the abs-pos list.  Callers should
   * use this function if they want to get the list acting as the fixed-pos item parent.
   */
  nsAbsoluteItems& GetFixedItems()
  {
    return mFixedPosIsAbsPos ? mAbsoluteItems : mFixedItems;
  }
  const nsAbsoluteItems& GetFixedItems() const
  {
    return mFixedPosIsAbsPos ? mAbsoluteItems : mFixedItems;
  }


  /**
   * class to automatically push and pop a pending binding in the frame
   * constructor state.  See nsCSSFrameConstructor::FrameConstructionItem
   * mPendingBinding documentation.
   */
  class PendingBindingAutoPusher;
  friend class PendingBindingAutoPusher;
  class MOZ_STACK_CLASS PendingBindingAutoPusher {
  public:
    PendingBindingAutoPusher(nsFrameConstructorState& aState,
                             PendingBinding* aPendingBinding) :
      mState(aState),
      mPendingBinding(aState.mCurrentPendingBindingInsertionPoint)
        {
          if (aPendingBinding) {
            aState.mCurrentPendingBindingInsertionPoint = aPendingBinding;
          }
        }

    ~PendingBindingAutoPusher()
      {
        mState.mCurrentPendingBindingInsertionPoint = mPendingBinding;
      }

  private:
    nsFrameConstructorState& mState;
    PendingBinding* mPendingBinding;
  };

  /**
   * Add a new pending binding to the list
   */
  void AddPendingBinding(PendingBinding* aPendingBinding) {
    if (mCurrentPendingBindingInsertionPoint) {
      mCurrentPendingBindingInsertionPoint->setPrevious(aPendingBinding);
    } else {
      mPendingBindings.insertBack(aPendingBinding);
    }
  }

protected:
  friend class nsFrameConstructorSaveState;

  /**
   * ProcessFrameInsertions takes the frames in aFrameItems and adds them as
   * kids to the aChildListID child list of |aFrameItems.containingBlock|.
   */
  void ProcessFrameInsertions(nsAbsoluteItems& aFrameItems,
                              ChildListID aChildListID);

  // Our list of all pending bindings.  When we're done, we need to call
  // AddToAttachedQueue on all of them, in order.
  LinkedList<PendingBinding> mPendingBindings;

  PendingBinding* mCurrentPendingBindingInsertionPoint;
};

nsFrameConstructorState::nsFrameConstructorState(nsIPresShell*          aPresShell,
                                                 nsIFrame*              aFixedContainingBlock,
                                                 nsIFrame*              aAbsoluteContainingBlock,
                                                 nsIFrame*              aFloatContainingBlock,
                                                 nsILayoutHistoryState* aHistoryState)
  : mPresContext(aPresShell->GetPresContext()),
    mPresShell(aPresShell),
    mFrameManager(aPresShell->FrameManager()),
#ifdef MOZ_XUL    
    mPopupItems(nullptr),
#endif
    mFixedItems(aFixedContainingBlock),
    mAbsoluteItems(aAbsoluteContainingBlock),
    mFloatedItems(aFloatContainingBlock),
    // See PushAbsoluteContaningBlock below
    mFrameState(aHistoryState),
    mAdditionalStateBits(0),
    // If the fixed-pos containing block is equal to the abs-pos containing
    // block, use the abs-pos containing block's abs-pos list for fixed-pos
	// frames.
    mFixedPosIsAbsPos(aFixedContainingBlock == aAbsoluteContainingBlock),
    mHavePendingPopupgroup(false),
    mCreatingExtraFrames(false),
    mTreeMatchContext(true, nsRuleWalker::eRelevantLinkUnvisited,
                      aPresShell->GetDocument()),
    mCurrentPendingBindingInsertionPoint(nullptr)
{
#ifdef MOZ_XUL
  nsIRootBox* rootBox = nsIRootBox::GetRootBox(aPresShell);
  if (rootBox) {
    mPopupItems.containingBlock = rootBox->GetPopupSetFrame();
  }
#endif
  MOZ_COUNT_CTOR(nsFrameConstructorState);
}

nsFrameConstructorState::nsFrameConstructorState(nsIPresShell* aPresShell,
                                                 nsIFrame*     aFixedContainingBlock,
                                                 nsIFrame*     aAbsoluteContainingBlock,
                                                 nsIFrame*     aFloatContainingBlock)
  : mPresContext(aPresShell->GetPresContext()),
    mPresShell(aPresShell),
    mFrameManager(aPresShell->FrameManager()),
#ifdef MOZ_XUL    
    mPopupItems(nullptr),
#endif
    mFixedItems(aFixedContainingBlock),
    mAbsoluteItems(aAbsoluteContainingBlock),
    mFloatedItems(aFloatContainingBlock),
    // See PushAbsoluteContaningBlock below
    mAdditionalStateBits(0),
    // If the fixed-pos containing block is equal to the abs-pos containing
    // block, use the abs-pos containing block's abs-pos list for fixed-pos
	// frames.
    mFixedPosIsAbsPos(aFixedContainingBlock == aAbsoluteContainingBlock),
    mHavePendingPopupgroup(false),
    mCreatingExtraFrames(false),
    mTreeMatchContext(true, nsRuleWalker::eRelevantLinkUnvisited,
                      aPresShell->GetDocument()),
    mCurrentPendingBindingInsertionPoint(nullptr)
{
#ifdef MOZ_XUL
  nsIRootBox* rootBox = nsIRootBox::GetRootBox(aPresShell);
  if (rootBox) {
    mPopupItems.containingBlock = rootBox->GetPopupSetFrame();
  }
#endif
  MOZ_COUNT_CTOR(nsFrameConstructorState);
  mFrameState = aPresShell->GetDocument()->GetLayoutHistoryState();
}

nsFrameConstructorState::~nsFrameConstructorState()
{
  // Frame order comparison functions only work properly when the placeholders
  // have been inserted into the frame tree. So for example if we have a new float
  // containing the placeholder for a new abs-pos frame, and we process the abs-pos
  // insertion first, then we won't be able to find the right place to insert in
  // in the abs-pos list. So put floats in first, because they can contain placeholders
  // for abs-pos and fixed-pos items whose containing blocks are outside the floats.
  // Then put abs-pos frames in, because they can contain placeholders for fixed-pos
  // items whose containing block is outside the abs-pos frames. 
  MOZ_COUNT_DTOR(nsFrameConstructorState);
  ProcessFrameInsertions(mFloatedItems, nsIFrame::kFloatList);
  ProcessFrameInsertions(mAbsoluteItems, nsIFrame::kAbsoluteList);
  ProcessFrameInsertions(mFixedItems, nsIFrame::kFixedList);
#ifdef MOZ_XUL
  ProcessFrameInsertions(mPopupItems, nsIFrame::kPopupList);
#endif
  for (int32_t i = mGeneratedTextNodesWithInitializer.Count() - 1; i >= 0; --i) {
    mGeneratedTextNodesWithInitializer[i]->
      DeleteProperty(nsGkAtoms::genConInitializerProperty);
  }
  if (!mPendingBindings.isEmpty()) {
    nsBindingManager* bindingManager = mPresShell->GetDocument()->BindingManager();
    do {
      nsAutoPtr<PendingBinding> pendingBinding;
      pendingBinding = mPendingBindings.popFirst();
      bindingManager->AddToAttachedQueue(pendingBinding->mBinding);
    } while (!mPendingBindings.isEmpty());
    mCurrentPendingBindingInsertionPoint = nullptr;
  }
}

static nsIFrame*
AdjustAbsoluteContainingBlock(nsIFrame* aContainingBlockIn)
{
  if (!aContainingBlockIn) {
    return nullptr;
  }
  
  // Always use the container's first continuation. (Inline frames can have
  // non-fluid bidi continuations...)
  return aContainingBlockIn->GetFirstContinuation();
}

void
nsFrameConstructorState::PushAbsoluteContainingBlock(nsIFrame* aNewAbsoluteContainingBlock,
                                                     nsIFrame* aPositionedFrame,
                                                     nsFrameConstructorSaveState& aSaveState)
{
  aSaveState.mItems = &mAbsoluteItems;
  aSaveState.mSavedItems = mAbsoluteItems;
  aSaveState.mChildListID = nsIFrame::kAbsoluteList;
  aSaveState.mState = this;
  aSaveState.mSavedFixedPosIsAbsPos = mFixedPosIsAbsPos;

  if (mFixedPosIsAbsPos) {
    // Since we're going to replace mAbsoluteItems, we need to save it into
    // mFixedItems now (and save the current value of mFixedItems).
    aSaveState.mSavedFixedItems = mFixedItems;
    mFixedItems = mAbsoluteItems;
  }

  mAbsoluteItems =
    nsAbsoluteItems(AdjustAbsoluteContainingBlock(aNewAbsoluteContainingBlock));

  /* See if we're wiring the fixed-pos and abs-pos lists together.  This happens iff
   * we're a transformed element.
   */
  mFixedPosIsAbsPos = aPositionedFrame &&
      aPositionedFrame->StyleDisplay()->HasTransform(aPositionedFrame);

  if (aNewAbsoluteContainingBlock) {
    aNewAbsoluteContainingBlock->MarkAsAbsoluteContainingBlock();
  }
}

void
nsFrameConstructorState::PushFloatContainingBlock(nsIFrame* aNewFloatContainingBlock,
                                                  nsFrameConstructorSaveState& aSaveState)
{
  NS_PRECONDITION(!aNewFloatContainingBlock ||
                  aNewFloatContainingBlock->IsFloatContainingBlock(),
                  "Please push a real float containing block!");
  aSaveState.mItems = &mFloatedItems;
  aSaveState.mSavedItems = mFloatedItems;
  aSaveState.mChildListID = nsIFrame::kFloatList;
  aSaveState.mState = this;
  mFloatedItems = nsAbsoluteItems(aNewFloatContainingBlock);
}

nsIFrame*
nsFrameConstructorState::GetGeometricParent(const nsStyleDisplay* aStyleDisplay,
                                            nsIFrame* aContentParentFrame) const
{
  NS_PRECONDITION(aStyleDisplay, "Must have display struct!");

  // If there is no container for a fixed, absolute, or floating root
  // frame, we will ignore the positioning.  This hack is originally
  // brought to you by the letter T: tables, since other roots don't
  // even call into this code.  See bug 178855.
  //
  // XXX Disabling positioning in this case is a hack.  If one was so inclined,
  // one could support this either by (1) inserting a dummy block between the
  // table and the canvas or (2) teaching the canvas how to reflow positioned
  // elements. (1) has the usual problems when multiple frames share the same
  // content (notice all the special cases in this file dealing with inner
  // tables and outer tables which share the same content). (2) requires some
  // work and possible factoring.
  //
  // XXXbz couldn't we just force position to "static" on roots and
  // float to "none"?  That's OK per CSS 2.1, as far as I can tell.
  
  if (aContentParentFrame && aContentParentFrame->IsSVGText()) {
    return aContentParentFrame;
  }

  if (aStyleDisplay->IsFloatingStyle() && mFloatedItems.containingBlock) {
    NS_ASSERTION(!aStyleDisplay->IsAbsolutelyPositionedStyle(),
                 "Absolutely positioned _and_ floating?");
    return mFloatedItems.containingBlock;
  }

  if (aStyleDisplay->mPosition == NS_STYLE_POSITION_ABSOLUTE &&
      mAbsoluteItems.containingBlock) {
    return mAbsoluteItems.containingBlock;
  }

  if (aStyleDisplay->mPosition == NS_STYLE_POSITION_FIXED &&
      GetFixedItems().containingBlock) {
    return GetFixedItems().containingBlock;
  }

  return aContentParentFrame;
}

void
nsFrameConstructorState::AddChild(nsIFrame* aNewFrame,
                                  nsFrameItems& aFrameItems,
                                  nsIContent* aContent,
                                  nsStyleContext* aStyleContext,
                                  nsIFrame* aParentFrame,
                                  bool aCanBePositioned,
                                  bool aCanBeFloated,
                                  bool aIsOutOfFlowPopup,
                                  bool aInsertAfter,
                                  nsIFrame* aInsertAfterFrame)
{
  NS_PRECONDITION(!aNewFrame->GetNextSibling(), "Shouldn't happen");
  
  const nsStyleDisplay* disp = aNewFrame->StyleDisplay();
  
  // The comments in GetGeometricParent regarding root table frames
  // all apply here, unfortunately.

  bool needPlaceholder = false;
  nsFrameState placeholderType;
  nsFrameItems* frameItems = &aFrameItems;
#ifdef MOZ_XUL
  if (MOZ_UNLIKELY(aIsOutOfFlowPopup)) {
      NS_ASSERTION(aNewFrame->GetParent() == mPopupItems.containingBlock,
                   "Popup whose parent is not the popup containing block?");
      NS_ASSERTION(mPopupItems.containingBlock, "Must have a popup set frame!");
      needPlaceholder = true;
      frameItems = &mPopupItems;
      placeholderType = PLACEHOLDER_FOR_POPUP;
  }
  else
#endif // MOZ_XUL
  if (aCanBeFloated && aNewFrame->IsFloating() &&
      mFloatedItems.containingBlock) {
    NS_ASSERTION(aNewFrame->GetParent() == mFloatedItems.containingBlock,
                 "Float whose parent is not the float containing block?");
    needPlaceholder = true;
    frameItems = &mFloatedItems;
    placeholderType = PLACEHOLDER_FOR_FLOAT;
  }
  else if (aCanBePositioned) {
    if (disp->mPosition == NS_STYLE_POSITION_ABSOLUTE &&
        mAbsoluteItems.containingBlock) {
      NS_ASSERTION(aNewFrame->GetParent() == mAbsoluteItems.containingBlock,
                   "Abs pos whose parent is not the abs pos containing block?");
      needPlaceholder = true;
      frameItems = &mAbsoluteItems;
      placeholderType = PLACEHOLDER_FOR_ABSPOS;
    }
    if (disp->mPosition == NS_STYLE_POSITION_FIXED &&
        GetFixedItems().containingBlock) {
      NS_ASSERTION(aNewFrame->GetParent() == GetFixedItems().containingBlock,
                   "Fixed pos whose parent is not the fixed pos containing block?");
      needPlaceholder = true;
      frameItems = &GetFixedItems();
      placeholderType = PLACEHOLDER_FOR_FIXEDPOS;
    }
  }

  if (needPlaceholder) {
    NS_ASSERTION(frameItems != &aFrameItems,
                 "Putting frame in-flow _and_ want a placeholder?");
    nsIFrame* placeholderFrame =
      nsCSSFrameConstructor::CreatePlaceholderFrameFor(mPresShell,
                                                       aContent,
                                                       aNewFrame,
                                                       aStyleContext,
                                                       aParentFrame,
                                                       nullptr,
                                                       placeholderType);

    placeholderFrame->AddStateBits(mAdditionalStateBits);
    // Add the placeholder frame to the flow
    aFrameItems.AddChild(placeholderFrame);
  }
#ifdef DEBUG
  else {
    NS_ASSERTION(aNewFrame->GetParent() == aParentFrame,
                 "In-flow frame has wrong parent");
  }
#endif

  if (aInsertAfter) {
    frameItems->InsertFrame(nullptr, aInsertAfterFrame, aNewFrame);
  } else {
    frameItems->AddChild(aNewFrame);
  }
}

void
nsFrameConstructorState::ProcessFrameInsertions(nsAbsoluteItems& aFrameItems,
                                                ChildListID aChildListID)
{
#define NS_NONXUL_LIST_TEST (&aFrameItems == &mFloatedItems &&            \
                             aChildListID == nsIFrame::kFloatList)    ||  \
                            (&aFrameItems == &mAbsoluteItems &&           \
                             aChildListID == nsIFrame::kAbsoluteList) ||  \
                            (&aFrameItems == &mFixedItems &&              \
                             aChildListID == nsIFrame::kFixedList)
#ifdef MOZ_XUL
  NS_PRECONDITION(NS_NONXUL_LIST_TEST ||
                  (&aFrameItems == &mPopupItems &&
                   aChildListID == nsIFrame::kPopupList), 
                  "Unexpected aFrameItems/aChildListID combination");
#else
  NS_PRECONDITION(NS_NONXUL_LIST_TEST,
                  "Unexpected aFrameItems/aChildListID combination");
#endif

  if (aFrameItems.IsEmpty()) {
    return;
  }
  
  nsIFrame* containingBlock = aFrameItems.containingBlock;

  NS_ASSERTION(containingBlock,
               "Child list without containing block?");

  if (aChildListID == nsIFrame::kFixedList) {
    // Put this frame on the transformed-frame's abs-pos list instead, if
    // it has abs-pos children instead of fixed-pos children.
    aChildListID = containingBlock->GetAbsoluteListID();
  }

  // Insert the frames hanging out in aItems.  We can use SetInitialChildList()
  // if the containing block hasn't been reflowed yet (so NS_FRAME_FIRST_REFLOW
  // is set) and doesn't have any frames in the aChildListID child list yet.
  const nsFrameList& childList = containingBlock->GetChildList(aChildListID);
  DebugOnly<nsresult> rv = NS_OK;
  if (childList.IsEmpty() &&
      (containingBlock->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
    // If we're injecting absolutely positioned frames, inject them on the
    // absolute containing block
    if (aChildListID == containingBlock->GetAbsoluteListID()) {
      rv = containingBlock->GetAbsoluteContainingBlock()->
           SetInitialChildList(containingBlock, aChildListID, aFrameItems);
    } else {
      rv = containingBlock->SetInitialChildList(aChildListID, aFrameItems);
    }
  } else {
    // Note that whether the frame construction context is doing an append or
    // not is not helpful here, since it could be appending to some frame in
    // the middle of the document, which means we're not necessarily
    // appending to the children of the containing block.
    //
    // We need to make sure the 'append to the end of document' case is fast.
    // So first test the last child of the containing block
    nsIFrame* lastChild = childList.LastChild();

    // CompareTreePosition uses placeholder hierarchy for out of flow frames,
    // so this will make out-of-flows respect the ordering of placeholders,
    // which is great because it takes care of anonymous content.
    nsIFrame* firstNewFrame = aFrameItems.FirstChild();  
    if (!lastChild ||
        nsLayoutUtils::CompareTreePosition(lastChild, firstNewFrame, containingBlock) < 0) {
      // no lastChild, or lastChild comes before the new children, so just append
      rv = mFrameManager->AppendFrames(containingBlock, aChildListID, aFrameItems);
    } else {
      // try the other children
      nsIFrame* insertionPoint = nullptr;
      for (nsIFrame* f = childList.FirstChild(); f != lastChild;
           f = f->GetNextSibling()) {
        int32_t compare =
          nsLayoutUtils::CompareTreePosition(f, firstNewFrame, containingBlock);
        if (compare > 0) {
          // f comes after the new children, so stop here and insert after
          // the previous frame
          break;
        }
        insertionPoint = f;
      }
      rv = mFrameManager->InsertFrames(containingBlock, aChildListID,
                                       insertionPoint, aFrameItems);
    }
  }

  NS_POSTCONDITION(aFrameItems.IsEmpty(), "How did that happen?");

  // XXXbz And if NS_FAILED(rv), what?  I guess we need to clean up the list
  // and deal with all the placeholders... but what if the placeholders aren't
  // in the document yet?  Could that happen?
  NS_ASSERTION(NS_SUCCEEDED(rv), "Frames getting lost!");
}


nsFrameConstructorSaveState::nsFrameConstructorSaveState()
  : mItems(nullptr),
    mSavedItems(nullptr),
    mChildListID(kPrincipalList),
    mState(nullptr),
    mSavedFixedItems(nullptr),
    mSavedFixedPosIsAbsPos(false)
{
}

nsFrameConstructorSaveState::~nsFrameConstructorSaveState()
{
  // Restore the state
  if (mItems) {
    NS_ASSERTION(mState, "Can't have mItems set without having a state!");
    mState->ProcessFrameInsertions(*mItems, mChildListID);
    *mItems = mSavedItems;
#ifdef DEBUG
    // We've transferred the child list, so drop the pointer we held to it.
    // Note that this only matters for the assert in ~nsAbsoluteItems.
    mSavedItems.Clear();
#endif
    if (mItems == &mState->mAbsoluteItems) {
      mState->mFixedPosIsAbsPos = mSavedFixedPosIsAbsPos;
      if (mSavedFixedPosIsAbsPos) {
        // mAbsoluteItems was moved to mFixedItems, so move mFixedItems back
        // and repair the old mFixedItems now.
        mState->mAbsoluteItems = mState->mFixedItems;
        mState->mFixedItems = mSavedFixedItems;
#ifdef DEBUG
        mSavedFixedItems.Clear();
#endif
      }
    }
    NS_ASSERTION(!mItems->LastChild() || !mItems->LastChild()->GetNextSibling(),
                 "Something corrupted our list");
  }
}

static 
bool IsBorderCollapse(nsIFrame* aFrame)
{
  for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent()) {
    if (nsGkAtoms::tableFrame == frame->GetType()) {
      return ((nsTableFrame*)frame)->IsBorderCollapse();
    }
  }
  NS_ASSERTION(false, "program error");
  return false;
}

/**
 * Moves aFrameList from aOldParent to aNewParent.  This updates the parent
 * pointer of the frames in the list, and reparents their views as needed.
 * nsFrame::SetParent sets the NS_FRAME_HAS_VIEW bit on aNewParent and its
 * ancestors as needed. Then it sets the list as the initial child list
 * on aNewParent, unless aNewParent either already has kids or has been
 * reflowed; in that case it appends the new frames.  Note that this
 * method differs from ReparentFrames in that it doesn't change the kids'
 * style contexts.
 */
// XXXbz Since this is only used for {ib} splits, could we just copy the view
// bits from aOldParent to aNewParent and then use the
// nsFrameList::ApplySetParent?  That would still leave us doing two passes
// over the list, of course; if we really wanted to we could factor out the
// relevant part of ReparentFrameViewList, I suppose...  Or just get rid of
// views, which would make most of this function go away.
static void
MoveChildrenTo(nsPresContext* aPresContext,
               nsIFrame* aOldParent,
               nsIFrame* aNewParent,
               nsFrameList& aFrameList)
{
  bool sameGrandParent = aOldParent->GetParent() == aNewParent->GetParent();

  if (aNewParent->HasView() || aOldParent->HasView() || !sameGrandParent) {
    // Move the frames into the new view
    nsContainerFrame::ReparentFrameViewList(aPresContext, aFrameList,
                                            aOldParent, aNewParent);
  }

  for (nsFrameList::Enumerator e(aFrameList); !e.AtEnd(); e.Next()) {
    e.get()->SetParent(aNewParent);
  }

  if (aNewParent->PrincipalChildList().IsEmpty() &&
      (aNewParent->GetStateBits() & NS_FRAME_FIRST_REFLOW)) {
    aNewParent->SetInitialChildList(kPrincipalList, aFrameList);
  } else {
    aNewParent->AppendFrames(kPrincipalList, aFrameList);
  }
}

//----------------------------------------------------------------------

nsCSSFrameConstructor::nsCSSFrameConstructor(nsIDocument *aDocument,
                                             nsIPresShell *aPresShell,
                                             nsStyleSet* aStyleSet)
  : nsFrameManager(aPresShell, aStyleSet)
  , mDocument(aDocument)
  , mRootElementFrame(nullptr)
  , mRootElementStyleFrame(nullptr)
  , mFixedContainingBlock(nullptr)
  , mDocElementContainingBlock(nullptr)
  , mGfxScrollFrame(nullptr)
  , mPageSequenceFrame(nullptr)
  , mCurrentDepth(0)
  , mUpdateCount(0)
  , mQuotesDirty(false)
  , mCountersDirty(false)
  , mIsDestroyingFrameTree(false)
  , mHasRootAbsPosContainingBlock(false)
{
#ifdef DEBUG
  static bool gFirstTime = true;
  if (gFirstTime) {
    gFirstTime = false;
    char* flags = PR_GetEnv("GECKO_FRAMECTOR_DEBUG_FLAGS");
    if (flags) {
      bool error = false;
      for (;;) {
        char* comma = PL_strchr(flags, ',');
        if (comma)
          *comma = '\0';

        bool found = false;
        FrameCtorDebugFlags* flag = gFlags;
        FrameCtorDebugFlags* limit = gFlags + NUM_DEBUG_FLAGS;
        while (flag < limit) {
          if (PL_strcasecmp(flag->name, flags) == 0) {
            *(flag->on) = true;
            printf("nsCSSFrameConstructor: setting %s debug flag on\n", flag->name);
            found = true;
            break;
          }
          ++flag;
        }

        if (! found)
          error = true;

        if (! comma)
          break;

        *comma = ',';
        flags = comma + 1;
      }

      if (error) {
        printf("Here are the available GECKO_FRAMECTOR_DEBUG_FLAGS:\n");
        FrameCtorDebugFlags* flag = gFlags;
        FrameCtorDebugFlags* limit = gFlags + NUM_DEBUG_FLAGS;
        while (flag < limit) {
          printf("  %s\n", flag->name);
          ++flag;
        }
        printf("Note: GECKO_FRAMECTOR_DEBUG_FLAGS is a comma separated list of flag\n");
        printf("names (no whitespace)\n");
      }
    }
  }
#endif
}

void
nsCSSFrameConstructor::NotifyDestroyingFrame(nsIFrame* aFrame)
{
  NS_PRECONDITION(mUpdateCount != 0,
                  "Should be in an update while destroying frames");

  if (aFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) {
    if (mQuoteList.DestroyNodesFor(aFrame))
      QuotesDirty();
  }

  if (mCounterManager.DestroyNodesFor(aFrame)) {
    // Technically we don't need to update anything if we destroyed only
    // USE nodes.  However, this is unlikely to happen in the real world
    // since USE nodes generally go along with INCREMENT nodes.
    CountersDirty();
  }

  RestyleManager()->NotifyDestroyingFrame(aFrame);

  nsFrameManager::NotifyDestroyingFrame(aFrame);
}

struct nsGenConInitializer {
  nsAutoPtr<nsGenConNode> mNode;
  nsGenConList*           mList;
  void (nsCSSFrameConstructor::*mDirtyAll)();
  
  nsGenConInitializer(nsGenConNode* aNode, nsGenConList* aList,
                      void (nsCSSFrameConstructor::*aDirtyAll)())
    : mNode(aNode), mList(aList), mDirtyAll(aDirtyAll) {}
};

static void
DestroyGenConInitializer(void*    aFrame,
                         nsIAtom* aPropertyName,
                         void*    aPropertyValue,
                         void*    aDtorData)
{
  delete static_cast<nsGenConInitializer*>(aPropertyValue);
}

already_AddRefed<nsIContent>
nsCSSFrameConstructor::CreateGenConTextNode(nsFrameConstructorState& aState,
                                            const nsString& aString,
                                            nsCOMPtr<nsIDOMCharacterData>* aText,
                                            nsGenConInitializer* aInitializer)
{
  nsRefPtr<nsTextNode> content = new nsTextNode(mDocument->NodeInfoManager());
  content->SetText(aString, false);
  if (aText) {
    *aText = content;
  }
  if (aInitializer) {
    content->SetProperty(nsGkAtoms::genConInitializerProperty, aInitializer,
                         DestroyGenConInitializer);
    aState.mGeneratedTextNodesWithInitializer.AppendObject(content);
  }
  return content.forget();
}

already_AddRefed<nsIContent>
nsCSSFrameConstructor::CreateGeneratedContent(nsFrameConstructorState& aState,
                                              nsIContent*     aParentContent,
                                              nsStyleContext* aStyleContext,
                                              uint32_t        aContentIndex)
{
  // Get the content value
  const nsStyleContentData &data =
    aStyleContext->StyleContent()->ContentAt(aContentIndex);
  nsStyleContentType type = data.mType;

  if (eStyleContentType_Image == type) {
    if (!data.mContent.mImage) {
      // CSS had something specified that couldn't be converted to an
      // image object
      return nullptr;
    }
    
    // Create an image content object and pass it the image request.
    // XXX Check if it's an image type we can handle...

    nsCOMPtr<nsINodeInfo> nodeInfo;
    nodeInfo = mDocument->NodeInfoManager()->
      GetNodeInfo(nsGkAtoms::mozgeneratedcontentimage, nullptr,
                  kNameSpaceID_XHTML, nsIDOMNode::ELEMENT_NODE);

    nsCOMPtr<nsIContent> content;
    NS_NewGenConImageContent(getter_AddRefs(content), nodeInfo.forget(),
                             data.mContent.mImage);
    return content.forget();
  }

  switch (type) {
  case eStyleContentType_String:
    return CreateGenConTextNode(aState,
                                nsDependentString(data.mContent.mString),
                                nullptr, nullptr);

  case eStyleContentType_Attr:
    {
      nsCOMPtr<nsIAtom> attrName;
      int32_t attrNameSpace = kNameSpaceID_None;
      nsAutoString contentString(data.mContent.mString);
      
      int32_t barIndex = contentString.FindChar('|'); // CSS namespace delimiter
      if (-1 != barIndex) {
        nsAutoString  nameSpaceVal;
        contentString.Left(nameSpaceVal, barIndex);
        nsresult error;
        attrNameSpace = nameSpaceVal.ToInteger(&error);
        contentString.Cut(0, barIndex + 1);
        if (contentString.Length()) {
          if (mDocument->IsHTML() && aParentContent->IsHTML()) {
            ToLowerCase(contentString);
          }
          attrName = do_GetAtom(contentString);
        }
      }
      else {
        if (mDocument->IsHTML() && aParentContent->IsHTML()) {
          ToLowerCase(contentString);
        }
        attrName = do_GetAtom(contentString);
      }

      if (!attrName) {
        return nullptr;
      }

      nsCOMPtr<nsIContent> content;
      NS_NewAttributeContent(mDocument->NodeInfoManager(),
                             attrNameSpace, attrName, getter_AddRefs(content));
      return content.forget();
    }

  case eStyleContentType_Counter:
  case eStyleContentType_Counters:
    {
      nsCSSValue::Array* counters = data.mContent.mCounters;
      nsCounterList* counterList = mCounterManager.CounterListFor(
          nsDependentString(counters->Item(0).GetStringBufferValue()));
      if (!counterList)
        return nullptr;

      nsCounterUseNode* node =
        new nsCounterUseNode(counters, aContentIndex,
                             type == eStyleContentType_Counters);

      nsGenConInitializer* initializer =
        new nsGenConInitializer(node, counterList,
                                &nsCSSFrameConstructor::CountersDirty);
      return CreateGenConTextNode(aState, EmptyString(), &node->mText,
                                  initializer);
    }

  case eStyleContentType_Image:
    NS_NOTREACHED("handled by if above");
    return nullptr;

  case eStyleContentType_OpenQuote:
  case eStyleContentType_CloseQuote:
  case eStyleContentType_NoOpenQuote:
  case eStyleContentType_NoCloseQuote:
    {
      nsQuoteNode* node =
        new nsQuoteNode(type, aContentIndex);

      nsGenConInitializer* initializer =
        new nsGenConInitializer(node, &mQuoteList,
                                &nsCSSFrameConstructor::QuotesDirty);
      return CreateGenConTextNode(aState, EmptyString(), &node->mText,
                                  initializer);
    }
  
  case eStyleContentType_AltContent:
    {
      // Use the "alt" attribute; if that fails and the node is an HTML
      // <input>, try the value attribute and then fall back to some default
      // localized text we have.
      // XXX what if the 'alt' attribute is added later, how will we
      // detect that and do the right thing here?
      if (aParentContent->HasAttr(kNameSpaceID_None, nsGkAtoms::alt)) {
        nsCOMPtr<nsIContent> content;
        NS_NewAttributeContent(mDocument->NodeInfoManager(),
                               kNameSpaceID_None, nsGkAtoms::alt, getter_AddRefs(content));
        return content.forget();
      }

      if (aParentContent->IsHTML() &&
          aParentContent->NodeInfo()->Equals(nsGkAtoms::input)) {
        if (aParentContent->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
          nsCOMPtr<nsIContent> content;
          NS_NewAttributeContent(mDocument->NodeInfoManager(),
                                 kNameSpaceID_None, nsGkAtoms::value, getter_AddRefs(content));
          return content.forget();
        }

        nsXPIDLString temp;
        nsContentUtils::GetLocalizedString(nsContentUtils::eFORMS_PROPERTIES,
                                           "Submit", temp);
        return CreateGenConTextNode(aState, temp, nullptr, nullptr);
      }

      break;
    }
  } // switch

  return nullptr;
}

/*
 * aParentFrame - the frame that should be the parent of the generated
 *   content.  This is the frame for the corresponding content node,
 *   which must not be a leaf frame.
 * 
 * Any items created are added to aItems.
 * 
 * We create an XML element (tag _moz_generated_content_before or
 * _moz_generated_content_after) representing the pseudoelement. We
 * create a DOM node for each 'content' item and make those nodes the
 * children of the XML element. Then we create a frame subtree for
 * the XML element as if it were a regular child of
 * aParentFrame/aParentContent, giving the XML element the ::before or
 * ::after style.
 */
void
nsCSSFrameConstructor::CreateGeneratedContentItem(nsFrameConstructorState& aState,
                                                  nsIFrame*        aParentFrame,
                                                  nsIContent*      aParentContent,
                                                  nsStyleContext*  aStyleContext,
                                                  nsCSSPseudoElements::Type aPseudoElement,
                                                  FrameConstructionItemList& aItems)
{
  // XXXbz is this ever true?
  if (!aParentContent->IsElement()) {
    NS_ERROR("Bogus generated content parent");
    return;
  }

  nsStyleSet *styleSet = mPresShell->StyleSet();

  // Probe for the existence of the pseudo-element
  nsRefPtr<nsStyleContext> pseudoStyleContext;
  pseudoStyleContext =
    styleSet->ProbePseudoElementStyle(aParentContent->AsElement(),
                                      aPseudoElement,
                                      aStyleContext,
                                      aState.mTreeMatchContext);
  if (!pseudoStyleContext)
    return;
  // |ProbePseudoStyleFor| checked the 'display' property and the
  // |ContentCount()| of the 'content' property for us.
  nsCOMPtr<nsINodeInfo> nodeInfo;
  nsIAtom* elemName = aPseudoElement == nsCSSPseudoElements::ePseudo_before ?
    nsGkAtoms::mozgeneratedcontentbefore : nsGkAtoms::mozgeneratedcontentafter;
  nodeInfo = mDocument->NodeInfoManager()->GetNodeInfo(elemName, nullptr,
                                                       kNameSpaceID_None,
                                                       nsIDOMNode::ELEMENT_NODE);
  nsCOMPtr<nsIContent> container;
  nsresult rv = NS_NewXMLElement(getter_AddRefs(container), nodeInfo.forget());
  if (NS_FAILED(rv))
    return;
  container->SetNativeAnonymous();

  rv = container->BindToTree(mDocument, aParentContent, aParentContent, true);
  if (NS_FAILED(rv)) {
    container->UnbindFromTree();
    return;
  }

  uint32_t contentCount = pseudoStyleContext->StyleContent()->ContentCount();
  for (uint32_t contentIndex = 0; contentIndex < contentCount; contentIndex++) {
    nsCOMPtr<nsIContent> content =
      CreateGeneratedContent(aState, aParentContent, pseudoStyleContext,
                             contentIndex);
    if (content) {
      container->AppendChildTo(content, false);
    }
  }

  AddFrameConstructionItemsInternal(aState, container, aParentFrame, elemName,
                                    kNameSpaceID_None, true,
                                    pseudoStyleContext,
                                    ITEM_IS_GENERATED_CONTENT, aItems);
}
    
/****************************************************
 **  BEGIN TABLE SECTION
 ****************************************************/

// The term pseudo frame is being used instead of anonymous frame, since anonymous
// frame has been used elsewhere to refer to frames that have generated content

// Return whether the given frame is a table pseudo-frame.  Note that
// cell-content and table-outer frames have pseudo-types, but are always
// created, even for non-anonymous cells and tables respectively.  So for those
// we have to examine the cell or table frame to see whether it's a pseudo
// frame.  In particular, a lone table caption will have an outer table as its
// parent, but will also trigger construction of an empty inner table, which
// will be the one we can examine to see whether the outer was a pseudo-frame.
static bool
IsTablePseudo(nsIFrame* aFrame)
{
  nsIAtom* pseudoType = aFrame->StyleContext()->GetPseudo();
  return pseudoType &&
    (pseudoType == nsCSSAnonBoxes::table ||
     pseudoType == nsCSSAnonBoxes::inlineTable ||
     pseudoType == nsCSSAnonBoxes::tableColGroup ||
     pseudoType == nsCSSAnonBoxes::tableRowGroup ||
     pseudoType == nsCSSAnonBoxes::tableRow ||
     pseudoType == nsCSSAnonBoxes::tableCell ||
     (pseudoType == nsCSSAnonBoxes::cellContent &&
      aFrame->GetParent()->StyleContext()->GetPseudo() ==
        nsCSSAnonBoxes::tableCell) ||
     (pseudoType == nsCSSAnonBoxes::tableOuter &&
      (aFrame->GetFirstPrincipalChild()->StyleContext()->GetPseudo() ==
         nsCSSAnonBoxes::table ||
       aFrame->GetFirstPrincipalChild()->StyleContext()->GetPseudo() ==
         nsCSSAnonBoxes::inlineTable)));
}

/* static */
nsCSSFrameConstructor::ParentType
nsCSSFrameConstructor::GetParentType(nsIAtom* aFrameType)
{
  if (aFrameType == nsGkAtoms::tableFrame) {
    return eTypeTable;
  }
  if (aFrameType == nsGkAtoms::tableRowGroupFrame) {
    return eTypeRowGroup;
  }
  if (aFrameType == nsGkAtoms::tableRowFrame) {
    return eTypeRow;
  }
  if (aFrameType == nsGkAtoms::tableColGroupFrame) {
    return eTypeColGroup;
  }

  return eTypeBlock;
}
           
static nsIFrame*
AdjustCaptionParentFrame(nsIFrame* aParentFrame) 
{
  if (nsGkAtoms::tableFrame == aParentFrame->GetType()) {
    return aParentFrame->GetParent();;
  }
  return aParentFrame;
}
 
/**
 * If the parent frame is a |tableFrame| and the child is a
 * |captionFrame|, then we want to insert the frames beneath the
 * |tableFrame|'s parent frame. Returns |true| if the parent frame
 * needed to be fixed up.
 */
static bool
GetCaptionAdjustedParent(nsIFrame*        aParentFrame,
                         const nsIFrame*  aChildFrame,
                         nsIFrame**       aAdjParentFrame)
{
  *aAdjParentFrame = aParentFrame;
  bool haveCaption = false;

  if (nsGkAtoms::tableCaptionFrame == aChildFrame->GetType()) {
    haveCaption = true;
    *aAdjParentFrame = AdjustCaptionParentFrame(aParentFrame);
  }
  return haveCaption;
}

void
nsCSSFrameConstructor::AdjustParentFrame(nsIFrame* &                  aParentFrame,
                                         const FrameConstructionData* aFCData,
                                         nsStyleContext*              aStyleContext)
{
  NS_PRECONDITION(aStyleContext, "Must have child's style context");
  NS_PRECONDITION(aFCData, "Must have frame construction data");

  bool tablePart = ((aFCData->mBits & FCDATA_IS_TABLE_PART) != 0);

  if (tablePart && aStyleContext->StyleDisplay()->mDisplay ==
      NS_STYLE_DISPLAY_TABLE_CAPTION) {
    aParentFrame = AdjustCaptionParentFrame(aParentFrame);
  }
}

// Pull all the captions present in aItems out  into aCaptions
static void
PullOutCaptionFrames(nsFrameItems& aItems, nsFrameItems& aCaptions)
{
  nsIFrame *child = aItems.FirstChild();
  while (child) {
    nsIFrame *nextSibling = child->GetNextSibling();
    if (nsGkAtoms::tableCaptionFrame == child->GetType()) {
      aItems.RemoveFrame(child);
      aCaptions.AddChild(child);
    }
    child = nextSibling;
  }
}


// Construct the outer, inner table frames and the children frames for the table. 
// XXX Page break frames for pseudo table frames are not constructed to avoid the risk
// associated with revising the pseudo frame mechanism. The long term solution
// of having frames handle page-break-before/after will solve the problem. 
nsIFrame*
nsCSSFrameConstructor::ConstructTable(nsFrameConstructorState& aState,
                                      FrameConstructionItem&   aItem,
                                      nsIFrame*                aParentFrame,
                                      const nsStyleDisplay*    aDisplay,
                                      nsFrameItems&            aFrameItems)
{
  NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE ||
                  aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_TABLE,
                  "Unexpected call");

  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;
  const uint32_t nameSpaceID = aItem.mNameSpaceID;

  // create the pseudo SC for the outer table as a child of the inner SC
  nsRefPtr<nsStyleContext> outerStyleContext;
  outerStyleContext = mPresShell->StyleSet()->
    ResolveAnonymousBoxStyle(nsCSSAnonBoxes::tableOuter, styleContext);

  // Create the outer table frame which holds the caption and inner table frame
  nsIFrame* newFrame;
  if (kNameSpaceID_MathML == nameSpaceID)
    newFrame = NS_NewMathMLmtableOuterFrame(mPresShell, outerStyleContext);
  else
    newFrame = NS_NewTableOuterFrame(mPresShell, outerStyleContext);

  nsIFrame* geometricParent =
    aState.GetGeometricParent(outerStyleContext->StyleDisplay(),
                              aParentFrame);

  // Init the table outer frame
  InitAndRestoreFrame(aState, content, geometricParent, newFrame);  

  // Create the inner table frame
  nsIFrame* innerFrame;
  if (kNameSpaceID_MathML == nameSpaceID)
    innerFrame = NS_NewMathMLmtableFrame(mPresShell, styleContext);
  else
    innerFrame = NS_NewTableFrame(mPresShell, styleContext);

  InitAndRestoreFrame(aState, content, newFrame, innerFrame);

  // Put the newly created frames into the right child list
  SetInitialSingleChild(newFrame, innerFrame);

  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);

  if (!mRootElementFrame) {
    // The frame we're constructing will be the root element frame.
    // Set mRootElementFrame before processing children.
    mRootElementFrame = newFrame;
  }

  nsFrameItems childItems;

  // Process children
  nsFrameConstructorSaveState absoluteSaveState;
  const nsStyleDisplay* display = outerStyleContext->StyleDisplay();

  // Mark the table frame as an absolute container if needed
  newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  if ((display->IsRelativelyPositionedStyle() ||
       display->IsAbsolutelyPositionedStyle() ||
       (display->HasTransformStyle() &&
        aParentFrame->IsFrameOfType(nsIFrame::eSupportsCSSTransforms))) &&
      !aParentFrame->IsSVGText()) {
    aState.PushAbsoluteContainingBlock(newFrame, newFrame, absoluteSaveState);
  }
  if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
    ConstructFramesFromItemList(aState, aItem.mChildItems,
                                innerFrame, childItems);
  } else {
    ProcessChildren(aState, content, styleContext, innerFrame,
                    true, childItems, false, aItem.mPendingBinding);
  }

  nsFrameItems captionItems;
  PullOutCaptionFrames(childItems, captionItems);

  // Set the inner table frame's initial primary list 
  innerFrame->SetInitialChildList(kPrincipalList, childItems);

  // Set the outer table frame's secondary childlist lists
  if (captionItems.NotEmpty()) {
    newFrame->SetInitialChildList(nsIFrame::kCaptionList, captionItems);
  }

  return newFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructTableRow(nsFrameConstructorState& aState,
                                         FrameConstructionItem&   aItem,
                                         nsIFrame*                aParentFrame,
                                         const nsStyleDisplay*    aDisplay,
                                         nsFrameItems&            aFrameItems)
{
  NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_ROW,
                  "Unexpected call");
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;
  const uint32_t nameSpaceID = aItem.mNameSpaceID;

  nsIFrame* newFrame;
  if (kNameSpaceID_MathML == nameSpaceID)
    newFrame = NS_NewMathMLmtrFrame(mPresShell, styleContext);
  else
    newFrame = NS_NewTableRowFrame(mPresShell, styleContext);

  InitAndRestoreFrame(aState, content, aParentFrame, newFrame);

  nsFrameItems childItems;
  if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
    ConstructFramesFromItemList(aState, aItem.mChildItems, newFrame,
                                childItems);
  } else {
    ProcessChildren(aState, content, styleContext, newFrame,
                    true, childItems, false, aItem.mPendingBinding);
  }

  newFrame->SetInitialChildList(kPrincipalList, childItems);
  aFrameItems.AddChild(newFrame);
  return newFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructTableCol(nsFrameConstructorState& aState,
                                         FrameConstructionItem&   aItem,
                                         nsIFrame*                aParentFrame,
                                         const nsStyleDisplay*    aStyleDisplay,
                                         nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;

  nsTableColFrame* colFrame = NS_NewTableColFrame(mPresShell, styleContext);
  InitAndRestoreFrame(aState, content, aParentFrame, colFrame);

  NS_ASSERTION(colFrame->StyleContext() == styleContext,
               "Unexpected style context");

  aFrameItems.AddChild(colFrame);

  // construct additional col frames if the col frame has a span > 1
  int32_t span = colFrame->GetSpan();
  for (int32_t spanX = 1; spanX < span; spanX++) {
    nsTableColFrame* newCol = NS_NewTableColFrame(mPresShell, styleContext);
    InitAndRestoreFrame(aState, content, aParentFrame, newCol, false);
    aFrameItems.LastChild()->SetNextContinuation(newCol);
    newCol->SetPrevContinuation(aFrameItems.LastChild());
    aFrameItems.AddChild(newCol);
    newCol->SetColType(eColAnonymousCol);
  }

  return colFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructTableCell(nsFrameConstructorState& aState,
                                          FrameConstructionItem&   aItem,
                                          nsIFrame*                aParentFrame,
                                          const nsStyleDisplay*    aDisplay,
                                          nsFrameItems&            aFrameItems)
{
  NS_PRECONDITION(aDisplay->mDisplay == NS_STYLE_DISPLAY_TABLE_CELL,
                  "Unexpected call");

  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;
  const uint32_t nameSpaceID = aItem.mNameSpaceID;

  bool borderCollapse = IsBorderCollapse(aParentFrame);
  nsIFrame* newFrame;
  // <mtable> is border separate in mathml.css and the MathML code doesn't implement
  // border collapse. For those users who style <mtable> with border collapse,
  // give them the default non-MathML table frames that understand border collapse.
  // This won't break us because MathML table frames are all subclasses of the default
  // table code, and so we can freely mix <mtable> with <mtr> or <tr>, <mtd> or <td>.
  // What will happen is just that non-MathML frames won't understand MathML attributes
  // and will therefore miss the special handling that the MathML code does.
  if (kNameSpaceID_MathML == nameSpaceID && !borderCollapse)
    newFrame = NS_NewMathMLmtdFrame(mPresShell, styleContext);
  else
    // Warning: If you change this and add a wrapper frame around table cell
    // frames, make sure Bug 368554 doesn't regress!
    // See IsInAutoWidthTableCellForQuirk() in nsImageFrame.cpp.    
    newFrame = NS_NewTableCellFrame(mPresShell, styleContext, borderCollapse);

  // Initialize the table cell frame
  InitAndRestoreFrame(aState, content, aParentFrame, newFrame);
  
  // Resolve pseudo style and initialize the body cell frame
  nsRefPtr<nsStyleContext> innerPseudoStyle;
  innerPseudoStyle = mPresShell->StyleSet()->
    ResolveAnonymousBoxStyle(nsCSSAnonBoxes::cellContent, styleContext);

  // Create a block frame that will format the cell's content
  bool isBlock;
  nsIFrame* cellInnerFrame;
  if (kNameSpaceID_MathML == nameSpaceID) {
    cellInnerFrame = NS_NewMathMLmtdInnerFrame(mPresShell, innerPseudoStyle);
    isBlock = false;
  } else {
    cellInnerFrame = NS_NewBlockFormattingContext(mPresShell, innerPseudoStyle);
    isBlock = true;
  }

  InitAndRestoreFrame(aState, content, newFrame, cellInnerFrame);

  nsFrameItems childItems;
  if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
    // Need to push ourselves as a float containing block.
    // XXXbz it might be nice to work on getting the parent
    // FrameConstructionItem down into ProcessChildren and just making use of
    // the push there, but that's a bit of work.
    nsFrameConstructorSaveState floatSaveState;
    if (!isBlock) { /* MathML case */
      aState.PushFloatContainingBlock(nullptr, floatSaveState);
    } else {
      aState.PushFloatContainingBlock(cellInnerFrame, floatSaveState);
    }

    ConstructFramesFromItemList(aState, aItem.mChildItems, cellInnerFrame,
                                childItems);
  } else {
    // Process the child content
    ProcessChildren(aState, content, styleContext, cellInnerFrame,
                    true, childItems, isBlock, aItem.mPendingBinding);
  }
  
  cellInnerFrame->SetInitialChildList(kPrincipalList, childItems);
  SetInitialSingleChild(newFrame, cellInnerFrame);
  aFrameItems.AddChild(newFrame);
  return newFrame;
}

static inline bool 
NeedFrameFor(const nsFrameConstructorState& aState,
             nsIFrame*   aParentFrame,
             nsIContent* aChildContent) 
{
  // XXX the GetContent() != aChildContent check is needed due to bug 135040.
  // Remove it once that's fixed.
  NS_PRECONDITION(!aChildContent->GetPrimaryFrame() ||
                  aState.mCreatingExtraFrames ||
                  aChildContent->GetPrimaryFrame()->GetContent() != aChildContent,
                  "Why did we get called?");

  // don't create a whitespace frame if aParentFrame doesn't want it.
  // always create frames for children in generated content. counter(),
  // quotes, and attr() content can easily change dynamically and we don't
  // want to be reconstructing frames. It's not even clear that these
  // should be considered ignorable just because they evaluate to
  // whitespace.

  // We could handle all this in CreateNeededTablePseudos or some other place
  // after we build our frame construction items, but that would involve
  // creating frame construction items for whitespace kids of
  // eExcludesIgnorableWhitespace frames, where we know we'll be dropping them
  // all anyway, and involve an extra walk down the frame construction item
  // list.
  if (!aParentFrame->IsFrameOfType(nsIFrame::eExcludesIgnorableWhitespace) ||
      aParentFrame->IsGeneratedContentFrame() ||
      !aChildContent->IsNodeOfType(nsINode::eTEXT)) {
    return true;
  }

  aChildContent->SetFlags(NS_CREATE_FRAME_IF_NON_WHITESPACE |
                          NS_REFRAME_IF_WHITESPACE);
  return !aChildContent->TextIsOnlyWhitespace();
}

/***********************************************
 * END TABLE SECTION
 ***********************************************/

static bool CheckOverflow(nsPresContext* aPresContext,
                            const nsStyleDisplay* aDisplay)
{
  if (aDisplay->mOverflowX == NS_STYLE_OVERFLOW_VISIBLE)
    return false;

  if (aDisplay->mOverflowX == NS_STYLE_OVERFLOW_CLIP)
    aPresContext->SetViewportOverflowOverride(NS_STYLE_OVERFLOW_HIDDEN,
                                              NS_STYLE_OVERFLOW_HIDDEN);
  else
    aPresContext->SetViewportOverflowOverride(aDisplay->mOverflowX,
                                              aDisplay->mOverflowY);
  return true;
}

/**
 * This checks the root element and the HTML BODY, if any, for an "overflow" property
 * that should be applied to the viewport. If one is found then we return the
 * element that we took the overflow from (which should then be treated as
 * "overflow:visible"), and we store the overflow style in the prescontext.
 * @return if scroll was propagated from some content node, the content node it
 *         was propagated from.
 */
nsIContent*
nsCSSFrameConstructor::PropagateScrollToViewport()
{
  // Set default
  nsPresContext* presContext = mPresShell->GetPresContext();
  presContext->SetViewportOverflowOverride(NS_STYLE_OVERFLOW_AUTO,
                                           NS_STYLE_OVERFLOW_AUTO);

  // We never mess with the viewport scroll state
  // when printing or in print preview
  if (presContext->IsPaginated()) {
    return nullptr;
  }

  Element* docElement = mDocument->GetRootElement();

  // Check the style on the document root element
  nsStyleSet *styleSet = mPresShell->StyleSet();
  nsRefPtr<nsStyleContext> rootStyle;
  rootStyle = styleSet->ResolveStyleFor(docElement, nullptr);
  if (!rootStyle) {
    return nullptr;
  }
  if (CheckOverflow(presContext, rootStyle->StyleDisplay())) {
    // tell caller we stole the overflow style from the root element
    return docElement;
  }
  
  // Don't look in the BODY for non-HTML documents or HTML documents
  // with non-HTML roots
  // XXX this should be earlier; we shouldn't even look at the document root
  // for non-HTML documents. Fix this once we support explicit CSS styling
  // of the viewport
  // XXX what about XHTML?
  nsCOMPtr<nsIDOMHTMLDocument> htmlDoc(do_QueryInterface(mDocument));
  if (!htmlDoc || !docElement->IsHTML()) {
    return nullptr;
  }
  
  nsCOMPtr<nsIDOMHTMLElement> body;
  htmlDoc->GetBody(getter_AddRefs(body));
  nsCOMPtr<nsIContent> bodyElement = do_QueryInterface(body);
  
  if (!bodyElement ||
      !bodyElement->NodeInfo()->Equals(nsGkAtoms::body)) {
    // The body is not a <body> tag, it's a <frameset>.
    return nullptr;
  }

  nsRefPtr<nsStyleContext> bodyStyle;
  bodyStyle = styleSet->ResolveStyleFor(bodyElement->AsElement(), rootStyle);
  if (!bodyStyle) {
    return nullptr;
  }

  if (CheckOverflow(presContext, bodyStyle->StyleDisplay())) {
    // tell caller we stole the overflow style from the body element
    return bodyElement;
  }

  return nullptr;
}

nsIFrame*
nsCSSFrameConstructor::ConstructDocElementFrame(Element*                 aDocElement,
                                                nsILayoutHistoryState*   aFrameState)
{
  NS_PRECONDITION(mFixedContainingBlock,
                  "No viewport?  Someone forgot to call ConstructRootFrame!");
  NS_PRECONDITION(mFixedContainingBlock == GetRootFrame(),
                  "Unexpected mFixedContainingBlock");
  NS_PRECONDITION(!mDocElementContainingBlock,
                  "Shouldn't have a doc element containing block here");

  // Make sure to call PropagateScrollToViewport before
  // SetUpDocElementContainingBlock, since it sets up our scrollbar state
  // properly.
#ifdef DEBUG
  nsIContent* propagatedScrollFrom =
#endif
    PropagateScrollToViewport();

  SetUpDocElementContainingBlock(aDocElement);

  NS_ASSERTION(mDocElementContainingBlock, "Should have parent by now");

  nsFrameConstructorState state(mPresShell, mFixedContainingBlock, nullptr,
                                nullptr, aFrameState);
  // Initialize the ancestor filter with null for now; we'll push
  // aDocElement once we finish resolving style for it.
  state.mTreeMatchContext.InitAncestors(nullptr);

  // XXXbz why, exactly?
  if (!mTempFrameTreeState)
    state.mPresShell->CaptureHistoryState(getter_AddRefs(mTempFrameTreeState));

  // Make sure that we'll handle restyles for this document element in
  // the future.  We need this, because the document element might
  // have stale restyle bits from a previous frame constructor for
  // this document.  Unlike in AddFrameConstructionItems, it's safe to
  // unset all element restyle flags, since we don't have any
  // siblings.
  aDocElement->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS);

  // --------- CREATE AREA OR BOX FRAME -------
  nsRefPtr<nsStyleContext> styleContext;
  styleContext = mPresShell->StyleSet()->ResolveStyleFor(aDocElement,
                                                         nullptr);

  const nsStyleDisplay* display = styleContext->StyleDisplay();

  // Ensure that our XBL bindings are installed.
  if (display->mBinding) {
    // Get the XBL loader.
    nsresult rv;
    bool resolveStyle;
    
    nsXBLService* xblService = nsXBLService::GetInstance();
    if (!xblService) {
      return nullptr;
    }

    nsRefPtr<nsXBLBinding> binding;
    rv = xblService->LoadBindings(aDocElement, display->mBinding->GetURI(),
                                  display->mBinding->mOriginPrincipal,
                                  getter_AddRefs(binding), &resolveStyle);
    if (NS_FAILED(rv) && rv != NS_ERROR_XBL_BLOCKED)
      return nullptr; // Binding will load asynchronously.

    if (binding) {
      // For backwards compat, keep firing the root's constructor
      // after all of its kids' constructors.  So tell the binding
      // manager about it right now.
      mDocument->BindingManager()->AddToAttachedQueue(binding);
    }

    if (resolveStyle) {
      styleContext = mPresShell->StyleSet()->ResolveStyleFor(aDocElement,
                                                             nullptr);
      display = styleContext->StyleDisplay();
    }
  }

  // --------- IF SCROLLABLE WRAP IN SCROLLFRAME --------

#ifdef DEBUG
  NS_ASSERTION(!display->IsScrollableOverflow() || 
               state.mPresContext->IsPaginated() ||
               propagatedScrollFrom == aDocElement,
               "Scrollbars should have been propagated to the viewport");
#endif

  if (MOZ_UNLIKELY(display->mDisplay == NS_STYLE_DISPLAY_NONE)) {
    SetUndisplayedContent(aDocElement, styleContext);
    return nullptr;
  }

  TreeMatchContext::AutoAncestorPusher
    ancestorPusher(true, state.mTreeMatchContext, aDocElement);

  // Make sure to start any background image loads for the root element now.
  styleContext->StartBackgroundImageLoads();

  nsFrameConstructorSaveState absoluteSaveState;
  if (mHasRootAbsPosContainingBlock) {
    // Push the absolute containing block now so we can absolutely position
    // the root element
    mDocElementContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
    state.PushAbsoluteContainingBlock(mDocElementContainingBlock,
                                      mDocElementContainingBlock,
                                      absoluteSaveState);
  }

  // The rules from CSS 2.1, section 9.2.4, have already been applied
  // by the style system, so we can assume that display->mDisplay is
  // either NONE, BLOCK, or TABLE.

  // contentFrame is the primary frame for the root element. newFrame
  // is the frame that will be the child of the initial containing block.
  // These are usually the same frame but they can be different, in
  // particular if the root frame is positioned, in which case
  // contentFrame is the out-of-flow frame and newFrame is the
  // placeholder.
  nsIFrame* contentFrame;
  nsIFrame* newFrame;
  bool processChildren = false;

  // Check whether we need to build a XUL box or SVG root frame
#ifdef MOZ_XUL
  if (aDocElement->IsXUL()) {
    contentFrame = NS_NewDocElementBoxFrame(mPresShell, styleContext);
    InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                        contentFrame);
    newFrame = contentFrame;
    processChildren = true;
  }
  else
#endif
  if (aDocElement->IsSVG()) {
    if (aDocElement->Tag() == nsGkAtoms::svg) {
      // We're going to call the right function ourselves, so no need to give a
      // function to this FrameConstructionData.

      // XXXbz on the other hand, if we converted this whole function to
      // FrameConstructionData/Item, then we'd need the right function
      // here... but would probably be able to get away with less code in this
      // function in general.
      // Use a null PendingBinding, since our binding is not in fact pending.
      static const FrameConstructionData rootSVGData = FCDATA_DECL(0, nullptr);
      nsRefPtr<nsStyleContext> extraRef(styleContext);
      FrameConstructionItem item(&rootSVGData, aDocElement,
                                 aDocElement->Tag(), kNameSpaceID_SVG,
                                 nullptr, extraRef.forget(), true);

      nsFrameItems frameItems;
      contentFrame = ConstructOuterSVG(state, item, mDocElementContainingBlock,
                                       styleContext->StyleDisplay(),
                                       frameItems);
      newFrame = frameItems.FirstChild();
      NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
    } else {
      return nullptr;
    }
  } else {
    bool docElemIsTable = (display->mDisplay == NS_STYLE_DISPLAY_TABLE);
    if (docElemIsTable) {
      // We're going to call the right function ourselves, so no need to give a
      // function to this FrameConstructionData.

      // XXXbz on the other hand, if we converted this whole function to
      // FrameConstructionData/Item, then we'd need the right function
      // here... but would probably be able to get away with less code in this
      // function in general.
      // Use a null PendingBinding, since our binding is not in fact pending.
      static const FrameConstructionData rootTableData = FCDATA_DECL(0, nullptr);
      nsRefPtr<nsStyleContext> extraRef(styleContext);
      FrameConstructionItem item(&rootTableData, aDocElement,
                                 aDocElement->Tag(), kNameSpaceID_None,
                                 nullptr, extraRef.forget(), true);

      nsFrameItems frameItems;
      // if the document is a table then just populate it.
      contentFrame = ConstructTable(state, item, mDocElementContainingBlock,
                                    styleContext->StyleDisplay(),
                                    frameItems);
      newFrame = frameItems.FirstChild();
      NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
    } else {
      contentFrame = NS_NewBlockFormattingContext(mPresShell, styleContext);
      nsFrameItems frameItems;
      // Use a null PendingBinding, since our binding is not in fact pending.
      ConstructBlock(state, display, aDocElement,
                     state.GetGeometricParent(display,
                                              mDocElementContainingBlock),
                     mDocElementContainingBlock, styleContext,
                     &contentFrame, frameItems,
                     display->IsPositioned(contentFrame) ? contentFrame : nullptr,
                     nullptr);
      newFrame = frameItems.FirstChild();
      NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
    }
  }

  MOZ_ASSERT(newFrame);
  MOZ_ASSERT(contentFrame);

  // set the primary frame
  aDocElement->SetPrimaryFrame(contentFrame);

  NS_ASSERTION(processChildren ? !mRootElementFrame :
                 mRootElementFrame == contentFrame,
               "unexpected mRootElementFrame");
  mRootElementFrame = contentFrame;

  // Figure out which frame has the main style for the document element,
  // assigning it to mRootElementStyleFrame.
  // Backgrounds should be propagated from that frame to the viewport.
  mRootElementStyleFrame = contentFrame->GetParentStyleContextFrame();
  bool isChild = mRootElementStyleFrame &&
                 mRootElementStyleFrame->GetParent() == contentFrame;
  if (!isChild) {
    mRootElementStyleFrame = mRootElementFrame;
  }

  if (processChildren) {
    // Still need to process the child content
    nsFrameItems childItems;

    NS_ASSERTION(!nsLayoutUtils::GetAsBlock(contentFrame) &&
                 !contentFrame->IsFrameOfType(nsIFrame::eSVG),
                 "Only XUL frames should reach here");
    // Use a null PendingBinding, since our binding is not in fact pending.
    ProcessChildren(state, aDocElement, styleContext, contentFrame, true,
                    childItems, false, nullptr);

    // Set the initial child lists
    contentFrame->SetInitialChildList(kPrincipalList, childItems);
  }

  SetInitialSingleChild(mDocElementContainingBlock, newFrame);

  return newFrame;
}


nsIFrame*
nsCSSFrameConstructor::ConstructRootFrame()
{
  AUTO_LAYOUT_PHASE_ENTRY_POINT(mPresShell->GetPresContext(), FrameC);

  nsStyleSet *styleSet = mPresShell->StyleSet();

  // Set up our style rule observer.
  // XXXbz wouldn't this make more sense as part of presshell init?
  {
    styleSet->SetBindingManager(mDocument->BindingManager());
  }

  // --------- BUILD VIEWPORT -----------
  nsIFrame*                 viewportFrame = nullptr;
  nsRefPtr<nsStyleContext> viewportPseudoStyle;

  viewportPseudoStyle =
    styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::viewport, nullptr);

  viewportFrame = NS_NewViewportFrame(mPresShell, viewportPseudoStyle);

  // XXXbz do we _have_ to pass a null content pointer to that frame?
  // Would it really kill us to pass in the root element or something?
  // What would that break?
  viewportFrame->Init(nullptr, nullptr, nullptr);

  // Bind the viewport frame to the root view
  nsView* rootView = mPresShell->GetViewManager()->GetRootView();
  viewportFrame->SetView(rootView);

  nsContainerFrame::SyncFrameViewProperties(mPresShell->GetPresContext(), viewportFrame,
                                            viewportPseudoStyle, rootView);
  nsContainerFrame::SyncWindowProperties(mPresShell->GetPresContext(), viewportFrame,
                                         rootView);

  // The viewport is the containing block for 'fixed' elements
  mFixedContainingBlock = viewportFrame;
  // Make it an absolute container for fixed-pos elements
  mFixedContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  mFixedContainingBlock->MarkAsAbsoluteContainingBlock();

  return viewportFrame;
}

void
nsCSSFrameConstructor::SetUpDocElementContainingBlock(nsIContent* aDocElement)
{
  NS_PRECONDITION(aDocElement, "No element?");
  NS_PRECONDITION(!aDocElement->GetParent(), "Not root content?");
  NS_PRECONDITION(aDocElement->GetCurrentDoc(), "Not in a document?");
  NS_PRECONDITION(aDocElement->GetCurrentDoc()->GetRootElement() ==
                  aDocElement, "Not the root of the document?");

  /*
    how the root frame hierarchy should look

  Galley presentation, non-XUL, with scrolling:
  
      ViewportFrame [fixed-cb]
        nsHTMLScrollFrame
          nsCanvasFrame [abs-cb]
            root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                nsTableOuterFrame, nsPlaceholderFrame)

  Galley presentation, XUL
  
      ViewportFrame [fixed-cb]
        nsRootBoxFrame
          root element frame (nsDocElementBoxFrame)

  Print presentation, non-XUL

      ViewportFrame
        nsSimplePageSequenceFrame
          nsPageFrame [fixed-cb]
            nsPageContentFrame
              nsCanvasFrame [abs-cb]
                root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                    nsTableOuterFrame, nsPlaceholderFrame)

  Print-preview presentation, non-XUL

      ViewportFrame
        nsHTMLScrollFrame
          nsSimplePageSequenceFrame
            nsPageFrame [fixed-cb]
              nsPageContentFrame
                nsCanvasFrame [abs-cb]
                  root element frame (nsBlockFrame, nsSVGOuterSVGFrame,
                                      nsTableOuterFrame, nsPlaceholderFrame)

  Print/print preview of XUL is not supported.
  [fixed-cb]: the default containing block for fixed-pos content
  [abs-cb]: the default containing block for abs-pos content
 
  Meaning of nsCSSFrameConstructor fields:
    mRootElementFrame is "root element frame".  This is the primary frame for
      the root element.
    mDocElementContainingBlock is the parent of mRootElementFrame
      (i.e. nsCanvasFrame or nsRootBoxFrame)
    mFixedContainingBlock is the [fixed-cb]
    mGfxScrollFrame is the nsHTMLScrollFrame mentioned above, or null if there isn't one
    mPageSequenceFrame is the nsSimplePageSequenceFrame, or null if there isn't one
  */

  // --------- CREATE ROOT FRAME -------


  // Create the root frame. The document element's frame is a child of the
  // root frame.
  //
  // The root frame serves two purposes:
  // - reserves space for any margins needed for the document element's frame
  // - renders the document element's background. This ensures the background covers
  //   the entire canvas as specified by the CSS2 spec

  nsPresContext* presContext = mPresShell->GetPresContext();
  bool isPaginated = presContext->IsRootPaginatedDocument();
  nsIFrame* viewportFrame = mFixedContainingBlock;
  nsStyleContext* viewportPseudoStyle = viewportFrame->StyleContext();

  nsIFrame* rootFrame = nullptr;
  nsIAtom* rootPseudo;
        
  if (!isPaginated) {
#ifdef MOZ_XUL
    if (aDocElement->IsXUL())
    {
      // pass a temporary stylecontext, the correct one will be set later
      rootFrame = NS_NewRootBoxFrame(mPresShell, viewportPseudoStyle);
    } else
#endif
    {
      // pass a temporary stylecontext, the correct one will be set later
      rootFrame = NS_NewCanvasFrame(mPresShell, viewportPseudoStyle);
      mHasRootAbsPosContainingBlock = true;
    }

    rootPseudo = nsCSSAnonBoxes::canvas;
    mDocElementContainingBlock = rootFrame;
  } else {
    // Create a page sequence frame
    rootFrame = NS_NewSimplePageSequenceFrame(mPresShell, viewportPseudoStyle);
    mPageSequenceFrame = rootFrame;
    rootPseudo = nsCSSAnonBoxes::pageSequence;
  }


  // --------- IF SCROLLABLE WRAP IN SCROLLFRAME --------

  // If the device supports scrolling (e.g., in galley mode on the screen and
  // for print-preview, but not when printing), then create a scroll frame that
  // will act as the scrolling mechanism for the viewport. 
  // XXX Do we even need a viewport when printing to a printer?

  // As long as the docshell doesn't prohibit it, and the device supports
  // it, create a scroll frame that will act as the scolling mechanism for
  // the viewport.
  //
  // Threre are three possible values stored in the docshell:
  //  1) nsIScrollable::Scrollbar_Never = no scrollbars
  //  2) nsIScrollable::Scrollbar_Auto = scrollbars appear if needed
  //  3) nsIScrollable::Scrollbar_Always = scrollbars always
  // Only need to create a scroll frame/view for cases 2 and 3.

  bool isHTML = aDocElement->IsHTML();
  bool isXUL = false;

  if (!isHTML) {
    isXUL = aDocElement->IsXUL();
  }

  // Never create scrollbars for XUL documents
  bool isScrollable = isPaginated ? presContext->HasPaginatedScrolling() : !isXUL;

  // We no longer need to do overflow propagation here. It's taken care of
  // when we construct frames for the element whose overflow might be
  // propagated
  NS_ASSERTION(!isScrollable || !isXUL,
               "XUL documents should never be scrollable - see above");

  nsIFrame* newFrame = rootFrame;
  nsRefPtr<nsStyleContext> rootPseudoStyle;
  // we must create a state because if the scrollbars are GFX it needs the 
  // state to build the scrollbar frames.
  nsFrameConstructorState state(mPresShell, nullptr, nullptr, nullptr);

  // Start off with the viewport as parent; we'll adjust it as needed.
  nsIFrame* parentFrame = viewportFrame;

  nsStyleSet* styleSet = mPresShell->StyleSet();
  // If paginated, make sure we don't put scrollbars in
  if (!isScrollable) {
    rootPseudoStyle = styleSet->ResolveAnonymousBoxStyle(rootPseudo,
                                                         viewportPseudoStyle);
  } else {
      if (rootPseudo == nsCSSAnonBoxes::canvas) {
        rootPseudo = nsCSSAnonBoxes::scrolledCanvas;
      } else {
        NS_ASSERTION(rootPseudo == nsCSSAnonBoxes::pageSequence,
                     "Unknown root pseudo");
        rootPseudo = nsCSSAnonBoxes::scrolledPageSequence;
      }

      // Build the frame. We give it the content we are wrapping which is the
      // document element, the root frame, the parent view port frame, and we
      // should get back the new frame and the scrollable view if one was
      // created.

      // resolve a context for the scrollframe
      nsRefPtr<nsStyleContext>  styleContext;
      styleContext = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::viewportScroll,
                                                        viewportPseudoStyle);

      // Note that the viewport scrollframe is always built with
      // overflow:auto style. This forces the scroll frame to create
      // anonymous content for both scrollbars. This is necessary even
      // if the HTML or BODY elements are overriding the viewport
      // scroll style to 'hidden' --- dynamic style changes might put
      // scrollbars back on the viewport and we don't want to have to
      // reframe the viewport to create the scrollbar content.
      newFrame = nullptr;
      rootPseudoStyle = BeginBuildingScrollFrame( state,
                                                  aDocElement,
                                                  styleContext,
                                                  viewportFrame,
                                                  rootPseudo,
                                                  true,
                                                  newFrame);
      parentFrame = newFrame;
      mGfxScrollFrame = newFrame;
  }
  
  rootFrame->SetStyleContextWithoutNotification(rootPseudoStyle);
  rootFrame->Init(aDocElement, parentFrame, nullptr);
  
  if (isScrollable) {
    FinishBuildingScrollFrame(parentFrame, rootFrame);
  }
  
  if (isPaginated) { // paginated
    // Create the first page
    // Set the initial child lists
    nsIFrame* canvasFrame;
    nsIFrame* pageFrame =
      ConstructPageFrame(mPresShell, presContext, rootFrame, nullptr,
                         canvasFrame);
    SetInitialSingleChild(rootFrame, pageFrame);

    // The eventual parent of the document element frame.
    // XXX should this be set for every new page (in ConstructPageFrame)?
    mDocElementContainingBlock = canvasFrame;
    mHasRootAbsPosContainingBlock = true;
  }

  if (viewportFrame->GetStateBits() & NS_FRAME_FIRST_REFLOW) {
    SetInitialSingleChild(viewportFrame, newFrame);
  } else {
    nsFrameList newFrameList(newFrame, newFrame);
    viewportFrame->AppendFrames(kPrincipalList, newFrameList);
  }
}

nsIFrame*
nsCSSFrameConstructor::ConstructPageFrame(nsIPresShell*  aPresShell,
                                          nsPresContext* aPresContext,
                                          nsIFrame*      aParentFrame,
                                          nsIFrame*      aPrevPageFrame,
                                          nsIFrame*&     aCanvasFrame)
{
  nsStyleContext* parentStyleContext = aParentFrame->StyleContext();
  nsStyleSet *styleSet = aPresShell->StyleSet();

  nsRefPtr<nsStyleContext> pagePseudoStyle;
  pagePseudoStyle = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::page,
                                                       parentStyleContext);

  nsIFrame* pageFrame = NS_NewPageFrame(aPresShell, pagePseudoStyle);

  // Initialize the page frame and force it to have a view. This makes printing of
  // the pages easier and faster.
  pageFrame->Init(nullptr, aParentFrame, aPrevPageFrame);

  nsRefPtr<nsStyleContext> pageContentPseudoStyle;
  pageContentPseudoStyle =
    styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::pageContent,
                                       pagePseudoStyle);

  nsIFrame* pageContentFrame = NS_NewPageContentFrame(aPresShell, pageContentPseudoStyle);

  // Initialize the page content frame and force it to have a view. Also make it the
  // containing block for fixed elements which are repeated on every page.
  nsIFrame* prevPageContentFrame = nullptr;
  if (aPrevPageFrame) {
    prevPageContentFrame = aPrevPageFrame->GetFirstPrincipalChild();
    NS_ASSERTION(prevPageContentFrame, "missing page content frame");
  }
  pageContentFrame->Init(nullptr, pageFrame, prevPageContentFrame);
  SetInitialSingleChild(pageFrame, pageContentFrame);
  mFixedContainingBlock = pageContentFrame;
  // Make it an absolute container for fixed-pos elements
  mFixedContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  mFixedContainingBlock->MarkAsAbsoluteContainingBlock();

  nsRefPtr<nsStyleContext> canvasPseudoStyle;
  canvasPseudoStyle = styleSet->ResolveAnonymousBoxStyle(nsCSSAnonBoxes::canvas,
                                                         pageContentPseudoStyle);

  aCanvasFrame = NS_NewCanvasFrame(aPresShell, canvasPseudoStyle);

  nsIFrame* prevCanvasFrame = nullptr;
  if (prevPageContentFrame) {
    prevCanvasFrame = prevPageContentFrame->GetFirstPrincipalChild();
    NS_ASSERTION(prevCanvasFrame, "missing canvas frame");
  }
  aCanvasFrame->Init(nullptr, pageContentFrame, prevCanvasFrame);
  SetInitialSingleChild(pageContentFrame, aCanvasFrame);
  return pageFrame;
}

/* static */
nsIFrame*
nsCSSFrameConstructor::CreatePlaceholderFrameFor(nsIPresShell*    aPresShell, 
                                                 nsIContent*      aContent,
                                                 nsIFrame*        aFrame,
                                                 nsStyleContext*  aStyleContext,
                                                 nsIFrame*        aParentFrame,
                                                 nsIFrame*        aPrevInFlow,
                                                 nsFrameState     aTypeBit)
{
  nsRefPtr<nsStyleContext> placeholderStyle = aPresShell->StyleSet()->
    ResolveStyleForNonElement(aStyleContext->GetParent());
  
  // The placeholder frame gets a pseudo style context
  nsPlaceholderFrame* placeholderFrame =
    (nsPlaceholderFrame*)NS_NewPlaceholderFrame(aPresShell, placeholderStyle,
                                                aTypeBit);

  placeholderFrame->Init(aContent, aParentFrame, aPrevInFlow);

  // The placeholder frame has a pointer back to the out-of-flow frame
  placeholderFrame->SetOutOfFlowFrame(aFrame);

  aFrame->AddStateBits(NS_FRAME_OUT_OF_FLOW);

  // Add mapping from absolutely positioned frame to its placeholder frame
  aPresShell->FrameManager()->RegisterPlaceholderFrame(placeholderFrame);

  return placeholderFrame;
}

// Clears any lazy bits set in the range [aStartContent, aEndContent).  If
// aEndContent is null, that means to clear bits in all siblings starting with
// aStartContent.  aStartContent must not be null unless aEndContent is also
// null.  We do this so that when new children are inserted under elements whose
// frame is a leaf the new children don't cause us to try to construct frames
// for the existing children again.
static inline void
ClearLazyBits(nsIContent* aStartContent, nsIContent* aEndContent)
{
  NS_PRECONDITION(aStartContent || !aEndContent,
                  "Must have start child if we have an end child");
  for (nsIContent* cur = aStartContent; cur != aEndContent;
       cur = cur->GetNextSibling()) {
    cur->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
  }
}

nsIFrame*
nsCSSFrameConstructor::ConstructSelectFrame(nsFrameConstructorState& aState,
                                            FrameConstructionItem&   aItem,
                                            nsIFrame*                aParentFrame,
                                            const nsStyleDisplay*    aStyleDisplay,
                                            nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;

  // Construct a frame-based listbox or combobox
  dom::HTMLSelectElement* sel = dom::HTMLSelectElement::FromContent(content);
  MOZ_ASSERT(sel);
  if (sel->IsCombobox()) {
    // Construct a frame-based combo box.
    // The frame-based combo box is built out of three parts. A display area, a button and
    // a dropdown list. The display area and button are created through anonymous content.
    // The drop-down list's frame is created explicitly. The combobox frame shares its content
    // with the drop-down list.
    uint32_t flags = NS_BLOCK_FLOAT_MGR;
    nsIFrame* comboboxFrame = NS_NewComboboxControlFrame(mPresShell, styleContext, flags);

    // Save the history state so we don't restore during construction
    // since the complete tree is required before we restore.
    nsILayoutHistoryState *historyState = aState.mFrameState;
    aState.mFrameState = nullptr;
    // Initialize the combobox frame
    InitAndRestoreFrame(aState, content,
                        aState.GetGeometricParent(aStyleDisplay, aParentFrame),
                        comboboxFrame);

    aState.AddChild(comboboxFrame, aFrameItems, content, styleContext,
                    aParentFrame);

    nsIComboboxControlFrame* comboBox = do_QueryFrame(comboboxFrame);
    NS_ASSERTION(comboBox, "NS_NewComboboxControlFrame returned frame that "
                 "doesn't implement nsIComboboxControlFrame");

    // Resolve pseudo element style for the dropdown list
    nsRefPtr<nsStyleContext> listStyle;
    listStyle = mPresShell->StyleSet()->
      ResolveAnonymousBoxStyle(nsCSSAnonBoxes::dropDownList, styleContext);

    // Create a listbox
    nsIFrame* listFrame = NS_NewListControlFrame(mPresShell, listStyle);

    // Notify the listbox that it is being used as a dropdown list.
    nsIListControlFrame * listControlFrame = do_QueryFrame(listFrame);
    if (listControlFrame) {
      listControlFrame->SetComboboxFrame(comboboxFrame);
    }
    // Notify combobox that it should use the listbox as it's popup
    comboBox->SetDropDown(listFrame);

    NS_ASSERTION(!listFrame->IsPositioned(),
                 "Ended up with positioned dropdown list somehow.");
    NS_ASSERTION(!listFrame->IsFloating(),
                 "Ended up with floating dropdown list somehow.");
      
    // Initialize the scroll frame positioned. Note that it is NOT
    // initialized as absolutely positioned.
    nsIFrame* scrolledFrame = NS_NewSelectsAreaFrame(mPresShell, styleContext, flags);

    InitializeSelectFrame(aState, listFrame, scrolledFrame, content,
                          comboboxFrame, listStyle, true,
                          aItem.mPendingBinding, aFrameItems);

    NS_ASSERTION(listFrame->GetView(), "ListFrame's view is nullptr");

    // Create display and button frames from the combobox's anonymous content.
    // The anonymous content is appended to existing anonymous content for this
    // element (the scrollbars).

    nsFrameItems childItems;
    CreateAnonymousFrames(aState, content, comboboxFrame,
                          aItem.mPendingBinding, childItems);

    comboboxFrame->SetInitialChildList(kPrincipalList, childItems);

    // Initialize the additional popup child list which contains the
    // dropdown list frame.
    nsFrameItems popupItems;
    popupItems.AddChild(listFrame);
    comboboxFrame->SetInitialChildList(nsIFrame::kSelectPopupList,
                                       popupItems);

    aState.mFrameState = historyState;
    if (aState.mFrameState) {
      // Restore frame state for the entire subtree of |comboboxFrame|.
      RestoreFrameState(comboboxFrame, aState.mFrameState);
    }
    return comboboxFrame;
  }

  // Listbox, not combobox
  nsIFrame* listFrame = NS_NewListControlFrame(mPresShell, styleContext);

  nsIFrame* scrolledFrame = NS_NewSelectsAreaFrame(
      mPresShell, styleContext, NS_BLOCK_FLOAT_MGR);

  // ******* this code stolen from Initialze ScrollFrame ********
  // please adjust this code to use BuildScrollFrame.

  InitializeSelectFrame(aState, listFrame, scrolledFrame, content,
                        aParentFrame, styleContext, false,
                        aItem.mPendingBinding, aFrameItems);

  return listFrame;
}

/**
 * Used to be InitializeScrollFrame but now it's only used for the select tag
 * But the select tag should really be fixed to use GFX scrollbars that can
 * be create with BuildScrollFrame.
 */
nsresult
nsCSSFrameConstructor::InitializeSelectFrame(nsFrameConstructorState& aState,
                                             nsIFrame*                scrollFrame,
                                             nsIFrame*                scrolledFrame,
                                             nsIContent*              aContent,
                                             nsIFrame*                aParentFrame,
                                             nsStyleContext*          aStyleContext,
                                             bool                     aBuildCombobox,
                                             PendingBinding*          aPendingBinding,
                                             nsFrameItems&            aFrameItems)
{
  const nsStyleDisplay* display = aStyleContext->StyleDisplay();

  // Initialize it
  nsIFrame* geometricParent = aState.GetGeometricParent(display, aParentFrame);
    
  // We don't call InitAndRestoreFrame for scrollFrame because we can only
  // restore the frame state after its parts have been created (in particular,
  // the scrollable view). So we have to split Init and Restore.

  // Initialize the frame
  scrollFrame->Init(aContent, geometricParent, nullptr);

  if (!aBuildCombobox) {
    aState.AddChild(scrollFrame, aFrameItems, aContent,
                    aStyleContext, aParentFrame);
  }
      
  if (aBuildCombobox) {
    nsContainerFrame::CreateViewForFrame(scrollFrame, true);
  }

  BuildScrollFrame(aState, aContent, aStyleContext, scrolledFrame,
                   geometricParent, scrollFrame);

  if (aState.mFrameState) {
    // Restore frame state for the scroll frame
    RestoreFrameStateFor(scrollFrame, aState.mFrameState);
  }

  // Process children
  nsFrameItems                childItems;

  ProcessChildren(aState, aContent, aStyleContext, scrolledFrame, false,
                  childItems, false, aPendingBinding);

  // Set the scrolled frame's initial child lists
  scrolledFrame->SetInitialChildList(kPrincipalList, childItems);
  return NS_OK;
}

nsIFrame*
nsCSSFrameConstructor::ConstructFieldSetFrame(nsFrameConstructorState& aState,
                                              FrameConstructionItem&   aItem,
                                              nsIFrame*                aParentFrame,
                                              const nsStyleDisplay*    aStyleDisplay,
                                              nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;

  nsIFrame* newFrame = NS_NewFieldSetFrame(mPresShell, styleContext);

  // Initialize it
  InitAndRestoreFrame(aState, content,
                      aState.GetGeometricParent(aStyleDisplay, aParentFrame),
                      newFrame);

  // Resolve style and initialize the frame
  nsRefPtr<nsStyleContext> fieldsetContentStyle;
  fieldsetContentStyle = mPresShell->StyleSet()->
    ResolveAnonymousBoxStyle(nsCSSAnonBoxes::fieldsetContent, styleContext);

  nsIFrame* blockFrame = NS_NewBlockFrame(mPresShell, fieldsetContentStyle,
                                          NS_BLOCK_FLOAT_MGR |
                                          NS_BLOCK_MARGIN_ROOT);
  InitAndRestoreFrame(aState, content, newFrame, blockFrame);

  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);
  
  // Process children
  nsFrameConstructorSaveState absoluteSaveState;
  nsFrameItems                childItems;

  newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  if (newFrame->IsPositioned()) {
    aState.PushAbsoluteContainingBlock(newFrame, newFrame, absoluteSaveState);
  }

  ProcessChildren(aState, content, styleContext, blockFrame, true,
                  childItems, true, aItem.mPendingBinding);

  nsFrameItems fieldsetKids;
  fieldsetKids.AddChild(blockFrame);

  for (nsFrameList::Enumerator e(childItems); !e.AtEnd(); e.Next()) {
    nsIFrame* child = e.get();
    if (child->GetContentInsertionFrame()->GetType() == nsGkAtoms::legendFrame) {
      // We want the legend to be the first frame in the fieldset child list.
      // That way the EventStateManager will do the right thing when tabbing
      // from a selection point within the legend (bug 236071), which is
      // used for implementing legend access keys (bug 81481).
      // GetAdjustedParentFrame() below depends on this frame order.
      childItems.RemoveFrame(child);
      // Make sure to reparent the legend so it has the fieldset as the parent.
      fieldsetKids.InsertFrame(newFrame, nullptr, child);
      break;
    }
  }

  // Set the inner frame's initial child lists
  blockFrame->SetInitialChildList(kPrincipalList, childItems);

  // Set the outer frame's initial child list
  newFrame->SetInitialChildList(kPrincipalList, fieldsetKids);

  newFrame->AddStateBits(NS_FRAME_MAY_HAVE_GENERATED_CONTENT);

  // Our new frame returned is the outer frame, which is the fieldset frame.
  return newFrame; 
}

static nsIFrame*
FindAncestorWithGeneratedContentPseudo(nsIFrame* aFrame)
{
  for (nsIFrame* f = aFrame->GetParent(); f; f = f->GetParent()) {
    NS_ASSERTION(f->IsGeneratedContentFrame(),
                 "should not have exited generated content");
    nsIAtom* pseudo = f->StyleContext()->GetPseudo();
    if (pseudo == nsCSSPseudoElements::before ||
        pseudo == nsCSSPseudoElements::after)
      return f;
  }
  return nullptr;
}

#define SIMPLE_FCDATA(_func) FCDATA_DECL(0, _func)
#define FULL_CTOR_FCDATA(_flags, _func)                             \
  { _flags | FCDATA_FUNC_IS_FULL_CTOR, { nullptr }, _func, nullptr }

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindTextData(nsIFrame* aParentFrame)
{
  if (aParentFrame && IsFrameForSVG(aParentFrame)) {
    nsIFrame *ancestorFrame =
      nsSVGUtils::GetFirstNonAAncestorFrame(aParentFrame);
    if (ancestorFrame) {
      if (NS_SVGTextCSSFramesEnabled()) {
        static const FrameConstructionData sSVGTextData =
          FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT | FCDATA_IS_SVG_TEXT,
                      NS_NewTextFrame);
        if (ancestorFrame->IsSVGText()) {
          return &sSVGTextData;
        }
      } else {
        static const FrameConstructionData sSVGGlyphData =
          SIMPLE_FCDATA(NS_NewSVGGlyphFrame);
        nsSVGTextContainerFrame* metrics = do_QueryFrame(ancestorFrame);
        if (metrics) {
          return &sSVGGlyphData;
        }
      }
    }
    return nullptr;
  }

  static const FrameConstructionData sTextData =
    FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT, NS_NewTextFrame);
  return &sTextData;
}

void
nsCSSFrameConstructor::ConstructTextFrame(const FrameConstructionData* aData,
                                          nsFrameConstructorState& aState,
                                          nsIContent*              aContent,
                                          nsIFrame*                aParentFrame,
                                          nsStyleContext*          aStyleContext,
                                          nsFrameItems&            aFrameItems)
{
  NS_PRECONDITION(aData, "Must have frame construction data");

  nsIFrame* newFrame = (*aData->mFunc.mCreationFunc)(mPresShell, aStyleContext);

  InitAndRestoreFrame(aState, aContent, aParentFrame, newFrame);

  // We never need to create a view for a text frame.

  if (newFrame->IsGeneratedContentFrame()) {
    nsAutoPtr<nsGenConInitializer> initializer;
    initializer =
      static_cast<nsGenConInitializer*>(
        aContent->UnsetProperty(nsGkAtoms::genConInitializerProperty));
    if (initializer) {
      if (initializer->mNode->InitTextFrame(initializer->mList,
              FindAncestorWithGeneratedContentPseudo(newFrame), newFrame)) {
        (this->*(initializer->mDirtyAll))();
      }
      initializer->mNode.forget();
    }
  }
  
  // Add the newly constructed frame to the flow
  aFrameItems.AddChild(newFrame);

  if (!aState.mCreatingExtraFrames)
    aContent->SetPrimaryFrame(newFrame);
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDataByInt(int32_t aInt,
                                     Element* aElement,
                                     nsStyleContext* aStyleContext,
                                     const FrameConstructionDataByInt* aDataPtr,
                                     uint32_t aDataLength)
{
  for (const FrameConstructionDataByInt *curData = aDataPtr,
         *endData = aDataPtr + aDataLength;
       curData != endData;
       ++curData) {
    if (curData->mInt == aInt) {
      const FrameConstructionData* data = &curData->mData;
      if (data->mBits & FCDATA_FUNC_IS_DATA_GETTER) {
        return data->mFunc.mDataGetter(aElement, aStyleContext);
      }

      return data;
    }
  }

  return nullptr;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDataByTag(nsIAtom* aTag,
                                     Element* aElement,
                                     nsStyleContext* aStyleContext,
                                     const FrameConstructionDataByTag* aDataPtr,
                                     uint32_t aDataLength)
{
  for (const FrameConstructionDataByTag *curData = aDataPtr,
         *endData = aDataPtr + aDataLength;
       curData != endData;
       ++curData) {
    if (*curData->mTag == aTag) {
      const FrameConstructionData* data = &curData->mData;
      if (data->mBits & FCDATA_FUNC_IS_DATA_GETTER) {
        return data->mFunc.mDataGetter(aElement, aStyleContext);
      }

      return data;
    }
  }

  return nullptr;
}

#define SUPPRESS_FCDATA() FCDATA_DECL(FCDATA_SUPPRESS_FRAME, nullptr)
#define SIMPLE_INT_CREATE(_int, _func) { _int, SIMPLE_FCDATA(_func) }
#define SIMPLE_INT_CHAIN(_int, _func)                       \
  { _int, FCDATA_DECL(FCDATA_FUNC_IS_DATA_GETTER, _func) }
#define COMPLEX_INT_CREATE(_int, _func)         \
  { _int, FULL_CTOR_FCDATA(0, _func) }

#define SIMPLE_TAG_CREATE(_tag, _func)          \
  { &nsGkAtoms::_tag, SIMPLE_FCDATA(_func) }
#define SIMPLE_TAG_CHAIN(_tag, _func)                                   \
  { &nsGkAtoms::_tag, FCDATA_DECL(FCDATA_FUNC_IS_DATA_GETTER,  _func) }
#define COMPLEX_TAG_CREATE(_tag, _func)             \
  { &nsGkAtoms::_tag, FULL_CTOR_FCDATA(0, _func) }

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindHTMLData(Element* aElement,
                                    nsIAtom* aTag,
                                    int32_t aNameSpaceID,
                                    nsIFrame* aParentFrame,
                                    nsStyleContext* aStyleContext)
{
  // Ignore the tag if it's not HTML content and if it doesn't extend (via XBL)
  // a valid HTML namespace.  This check must match the one in
  // ShouldHaveFirstLineStyle.
  if (aNameSpaceID != kNameSpaceID_XHTML) {
    return nullptr;
  }

  NS_ASSERTION(!aParentFrame ||
               aParentFrame->StyleContext()->GetPseudo() !=
                 nsCSSAnonBoxes::fieldsetContent ||
               aParentFrame->GetParent()->GetType() == nsGkAtoms::fieldSetFrame,
               "Unexpected parent for fieldset content anon box");
  if (aTag == nsGkAtoms::legend &&
      (!aParentFrame ||
       (aParentFrame->GetType() != nsGkAtoms::fieldSetFrame &&
        aParentFrame->StyleContext()->GetPseudo() !=
          nsCSSAnonBoxes::fieldsetContent) ||
       !aElement->GetParent() ||
       !aElement->GetParent()->IsHTML(nsGkAtoms::fieldset) ||
       aStyleContext->StyleDisplay()->IsFloatingStyle() ||
       aStyleContext->StyleDisplay()->IsAbsolutelyPositionedStyle())) {
    // <legend> is only special inside fieldset, check both the frame tree
    // parent and content tree parent due to XBL issues. For floated or
    // absolutely positioned legends we want to construct by display type and
    // not do special legend stuff.
    // XXXbz it would be nice if we could just decide this based on the parent
    // tag, and hence just use a SIMPLE_TAG_CHAIN for legend below, but the
    // fact that with XBL we could end up with this legend element in some
    // totally weird insertion point makes that chancy, I think.
    return nullptr;
  }

  static const FrameConstructionDataByTag sHTMLData[] = {
    SIMPLE_TAG_CHAIN(img, nsCSSFrameConstructor::FindImgData),
    SIMPLE_TAG_CHAIN(mozgeneratedcontentimage,
                     nsCSSFrameConstructor::FindImgData),
    { &nsGkAtoms::br,
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT | FCDATA_IS_LINE_BREAK,
                  NS_NewBRFrame) },
    SIMPLE_TAG_CREATE(wbr, NS_NewWBRFrame),
    SIMPLE_TAG_CHAIN(input, nsCSSFrameConstructor::FindInputData),
    SIMPLE_TAG_CREATE(textarea, NS_NewTextControlFrame),
    COMPLEX_TAG_CREATE(select, &nsCSSFrameConstructor::ConstructSelectFrame),
    SIMPLE_TAG_CHAIN(object, nsCSSFrameConstructor::FindObjectData),
    SIMPLE_TAG_CHAIN(applet, nsCSSFrameConstructor::FindObjectData),
    SIMPLE_TAG_CHAIN(embed, nsCSSFrameConstructor::FindObjectData),
    COMPLEX_TAG_CREATE(fieldset,
                       &nsCSSFrameConstructor::ConstructFieldSetFrame),
    { &nsGkAtoms::legend,
      FCDATA_DECL(FCDATA_ALLOW_BLOCK_STYLES | FCDATA_MAY_NEED_SCROLLFRAME,
                  NS_NewLegendFrame) },
    SIMPLE_TAG_CREATE(frameset, NS_NewHTMLFramesetFrame),
    SIMPLE_TAG_CREATE(iframe, NS_NewSubDocumentFrame),
    { &nsGkAtoms::button,
      FCDATA_WITH_WRAPPING_BLOCK(FCDATA_ALLOW_BLOCK_STYLES,
                                 NS_NewHTMLButtonControlFrame,
                                 nsCSSAnonBoxes::buttonContent) },
    SIMPLE_TAG_CHAIN(canvas, nsCSSFrameConstructor::FindCanvasData),
    SIMPLE_TAG_CREATE(video, NS_NewHTMLVideoFrame),
    SIMPLE_TAG_CREATE(audio, NS_NewHTMLVideoFrame),
    SIMPLE_TAG_CREATE(progress, NS_NewProgressFrame),
    SIMPLE_TAG_CREATE(meter, NS_NewMeterFrame)
  };

  return FindDataByTag(aTag, aElement, aStyleContext, sHTMLData,
                       ArrayLength(sHTMLData));
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindImgData(Element* aElement,
                                   nsStyleContext* aStyleContext)
{
  if (!nsImageFrame::ShouldCreateImageFrameFor(aElement, aStyleContext)) {
    return nullptr;
  }

  static const FrameConstructionData sImgData = SIMPLE_FCDATA(NS_NewImageFrame);
  return &sImgData;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindImgControlData(Element* aElement,
                                          nsStyleContext* aStyleContext)
{
  if (!nsImageFrame::ShouldCreateImageFrameFor(aElement, aStyleContext)) {
    return nullptr;
  }

  static const FrameConstructionData sImgControlData =
    SIMPLE_FCDATA(NS_NewImageControlFrame);
  return &sImgControlData;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindInputData(Element* aElement,
                                     nsStyleContext* aStyleContext)
{
  static const FrameConstructionDataByInt sInputData[] = {
    SIMPLE_INT_CREATE(NS_FORM_INPUT_CHECKBOX, NS_NewGfxCheckboxControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_RADIO, NS_NewGfxRadioControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_FILE, NS_NewFileControlFrame),
    SIMPLE_INT_CHAIN(NS_FORM_INPUT_IMAGE,
                     nsCSSFrameConstructor::FindImgControlData),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_EMAIL, NS_NewTextControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_SEARCH, NS_NewTextControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_TEXT, NS_NewTextControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_TEL, NS_NewTextControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_URL, NS_NewTextControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_RANGE, NS_NewRangeFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_PASSWORD, NS_NewTextControlFrame),
    // TODO: this is temporary until a frame is written: bug 635240.
    SIMPLE_INT_CREATE(NS_FORM_INPUT_NUMBER, NS_NewTextControlFrame),
    // TODO: this is temporary until a frame is written: bug 773205.
    SIMPLE_INT_CREATE(NS_FORM_INPUT_DATE, NS_NewTextControlFrame),
    // TODO: this is temporary until a frame is written: bug 773205
    SIMPLE_INT_CREATE(NS_FORM_INPUT_TIME, NS_NewTextControlFrame),
    { NS_FORM_INPUT_SUBMIT,
      FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                 nsCSSAnonBoxes::buttonContent) },
    { NS_FORM_INPUT_RESET,
      FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                 nsCSSAnonBoxes::buttonContent) },
    { NS_FORM_INPUT_BUTTON,
      FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewGfxButtonControlFrame,
                                 nsCSSAnonBoxes::buttonContent) }
    // Keeping hidden inputs out of here on purpose for so they get frames by
    // display (in practice, none).
  };

  nsCOMPtr<nsIFormControl> control = do_QueryInterface(aElement);
  NS_ASSERTION(control, "input doesn't implement nsIFormControl?");

  return FindDataByInt(control->GetType(), aElement, aStyleContext,
                       sInputData, ArrayLength(sInputData));
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindObjectData(Element* aElement,
                                      nsStyleContext* aStyleContext)
{
  // GetDisplayedType isn't necessarily nsIObjectLoadingContent::TYPE_NULL for
  // cases when the object is broken/suppressed/etc (e.g. a broken image), but
  // we want to treat those cases as TYPE_NULL
  uint32_t type;
  if (aElement->State().HasAtLeastOneOfStates(NS_EVENT_STATE_BROKEN |
                                              NS_EVENT_STATE_USERDISABLED |
                                              NS_EVENT_STATE_SUPPRESSED)) {
    type = nsIObjectLoadingContent::TYPE_NULL;
  } else {
    nsCOMPtr<nsIObjectLoadingContent> objContent(do_QueryInterface(aElement));
    NS_ASSERTION(objContent,
                 "applet, embed and object must implement "
                 "nsIObjectLoadingContent!");

    objContent->GetDisplayedType(&type);
  }

  static const FrameConstructionDataByInt sObjectData[] = {
    SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_LOADING,
                      NS_NewEmptyFrame),
    SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_PLUGIN,
                      NS_NewObjectFrame),
    SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_IMAGE,
                      NS_NewImageFrame),
    SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_DOCUMENT,
                      NS_NewSubDocumentFrame)
    // Nothing for TYPE_NULL so we'll construct frames by display there
  };

  return FindDataByInt((int32_t)type, aElement, aStyleContext,
                       sObjectData, ArrayLength(sObjectData));
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindCanvasData(Element* aElement,
                                      nsStyleContext* aStyleContext)
{
  // We want to check whether script is enabled on the document that
  // could be painting to the canvas.  That's the owner document of
  // the canvas, except when the owner document is a static document,
  // in which case it's the original document it was cloned from.
  nsIDocument* doc = aElement->OwnerDoc();
  if (doc->IsStaticDocument()) {
    doc = doc->GetOriginalDocument();
  }
  if (!doc->IsScriptEnabled()) {
    return nullptr;
  }

  static const FrameConstructionData sCanvasData =
    FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewHTMLCanvasFrame,
                               nsCSSAnonBoxes::htmlCanvasContent);
  return &sCanvasData;
}

void
nsCSSFrameConstructor::ConstructFrameFromItemInternal(FrameConstructionItem& aItem,
                                                      nsFrameConstructorState& aState,
                                                      nsIFrame* aParentFrame,
                                                      nsFrameItems& aFrameItems)
{
  const FrameConstructionData* data = aItem.mFCData;
  NS_ASSERTION(data, "Must have frame construction data");

  uint32_t bits = data->mBits;

  NS_ASSERTION(!(bits & FCDATA_FUNC_IS_DATA_GETTER),
               "Should have dealt with this inside the data finder");

  // Some sets of bits are not compatible with each other
#define CHECK_ONLY_ONE_BIT(_bit1, _bit2)               \
  NS_ASSERTION(!(bits & _bit1) || !(bits & _bit2),     \
               "Only one of these bits should be set")
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_FORCE_NULL_ABSPOS_CONTAINER);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_WRAP_KIDS_IN_BLOCKS);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_MAY_NEED_SCROLLFRAME);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_IS_POPUP);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_SKIP_ABSPOS_PUSH);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR,
                     FCDATA_DISALLOW_GENERATED_CONTENT);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR, FCDATA_ALLOW_BLOCK_STYLES);
  CHECK_ONLY_ONE_BIT(FCDATA_FUNC_IS_FULL_CTOR,
                     FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS);
  CHECK_ONLY_ONE_BIT(FCDATA_WRAP_KIDS_IN_BLOCKS,
                     FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS);
#undef CHECK_ONLY_ONE_BIT
  NS_ASSERTION(!(bits & FCDATA_FORCED_NON_SCROLLABLE_BLOCK) ||
               ((bits & FCDATA_FUNC_IS_FULL_CTOR) &&
                data->mFullConstructor ==
                  &nsCSSFrameConstructor::ConstructNonScrollableBlock),
               "Unexpected FCDATA_FORCED_NON_SCROLLABLE_BLOCK flag");

  // Don't create a subdocument frame for iframes if we're creating extra frames
  if (aState.mCreatingExtraFrames && aItem.mContent->IsHTML() &&
      aItem.mContent->Tag() == nsGkAtoms::iframe)
  {
    return;
  }

  nsStyleContext* const styleContext = aItem.mStyleContext;
  const nsStyleDisplay* display = styleContext->StyleDisplay();
  nsIContent* const content = aItem.mContent;

  // Get the parent of the content and check if it is a XBL children element.
  // Push the children element as an ancestor here because it does
  // not have a frame and would not otherwise be pushed as an ancestor. It is
  // necessary to do so in order to correctly handle style resolution on
  // descendants.
  nsIContent* parent = content->GetParent();
  bool pushInsertionPoint = aState.mTreeMatchContext.mAncestorFilter.HasFilter() &&
    parent && parent->IsActiveChildrenElement();
  TreeMatchContext::AutoAncestorPusher
    insertionPointPusher(pushInsertionPoint,
                         aState.mTreeMatchContext,
                         parent && parent->IsElement() ? parent->AsElement() : nullptr);

  // Push the content as a style ancestor now, so we don't have to do
  // it in our various full-constructor functions.  In particular,
  // since a number of full-constructor functions don't actually call
  // ProcessChildren in some cases (e.g. for CSS anonymous table boxes
  // or for situations where only anonymouse children are having
  // frames constructed), this is the best place to bottleneck the
  // pushing of the content instead of having to do it in multiple
  // places.
  TreeMatchContext::AutoAncestorPusher
    ancestorPusher(aState.mTreeMatchContext.mAncestorFilter.HasFilter(),
                   aState.mTreeMatchContext,
                   content->IsElement() ? content->AsElement() : nullptr);

  nsIFrame* newFrame;
  nsIFrame* primaryFrame;
  if (bits & FCDATA_FUNC_IS_FULL_CTOR) {
    newFrame =
      (this->*(data->mFullConstructor))(aState, aItem, aParentFrame,
                                        display, aFrameItems);
    MOZ_ASSERT(newFrame, "Full constructor failed");
    primaryFrame = newFrame;
  } else {
    newFrame =
      (*data->mFunc.mCreationFunc)(mPresShell, styleContext);

    bool allowOutOfFlow = !(bits & FCDATA_DISALLOW_OUT_OF_FLOW);
    bool isPopup = aItem.mIsPopup;
    NS_ASSERTION(!isPopup ||
                 (aState.mPopupItems.containingBlock &&
                  aState.mPopupItems.containingBlock->GetType() ==
                    nsGkAtoms::popupSetFrame),
                 "Should have a containing block here!");

    nsIFrame* geometricParent =
      isPopup ? aState.mPopupItems.containingBlock :
      (allowOutOfFlow ? aState.GetGeometricParent(display, aParentFrame)
                      : aParentFrame);

    // Must init frameToAddToList to null, since it's inout
    nsIFrame* frameToAddToList = nullptr;
    if ((bits & FCDATA_MAY_NEED_SCROLLFRAME) &&
        display->IsScrollableOverflow()) {
      BuildScrollFrame(aState, content, styleContext, newFrame,
                       geometricParent, frameToAddToList);
    } else {
      InitAndRestoreFrame(aState, content, geometricParent, newFrame);
      // See whether we need to create a view
      nsContainerFrame::CreateViewForFrame(newFrame, false);
      frameToAddToList = newFrame;
    }

    // Use frameToAddToList as the primary frame.  In the non-scrollframe case
    // they're equal, but in the scrollframe case newFrame is the scrolled
    // frame, while frameToAddToList is the scrollframe (and should be the
    // primary frame).
    primaryFrame = frameToAddToList;

    // If we need to create a block formatting context to wrap our
    // kids, do it now.
    const nsStyleDisplay* maybeAbsoluteContainingBlockDisplay = display;
    nsIFrame* maybeAbsoluteContainingBlock = newFrame;
    nsIFrame* possiblyLeafFrame = newFrame;
    if (bits & FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS) {
      nsRefPtr<nsStyleContext> blockContext;
      blockContext =
        mPresShell->StyleSet()->ResolveAnonymousBoxStyle(*data->mAnonBoxPseudo,
                                                         styleContext);
      nsIFrame* blockFrame =
        NS_NewBlockFormattingContext(mPresShell, blockContext);

      InitAndRestoreFrame(aState, content, newFrame, blockFrame);

      SetInitialSingleChild(newFrame, blockFrame);

      // Now figure out whether newFrame or blockFrame should be the
      // absolute container.  It should be the latter if it's
      // positioned, otherwise the former.
      const nsStyleDisplay* blockDisplay = blockContext->StyleDisplay();
      if (blockDisplay->IsPositioned(blockFrame)) {
        maybeAbsoluteContainingBlockDisplay = blockDisplay;
        maybeAbsoluteContainingBlock = blockFrame;
      }
      
      // Our kids should go into the blockFrame
      newFrame = blockFrame;
    }

    aState.AddChild(frameToAddToList, aFrameItems, content, styleContext,
                    aParentFrame, allowOutOfFlow, allowOutOfFlow, isPopup);

#ifdef MOZ_XUL
    // Icky XUL stuff, sadly

    if (aItem.mIsRootPopupgroup) {
      NS_ASSERTION(nsIRootBox::GetRootBox(mPresShell) &&
                   nsIRootBox::GetRootBox(mPresShell)->GetPopupSetFrame() ==
                     newFrame,
                   "Unexpected PopupSetFrame");
      aState.mPopupItems.containingBlock = newFrame;
      aState.mHavePendingPopupgroup = false;
    }
#endif /* MOZ_XUL */

    // Process the child content if requested
    nsFrameItems childItems;
    nsFrameConstructorSaveState absoluteSaveState;

    if (bits & FCDATA_FORCE_NULL_ABSPOS_CONTAINER) {
      aState.PushAbsoluteContainingBlock(nullptr, nullptr, absoluteSaveState);
    } else if (!(bits & FCDATA_SKIP_ABSPOS_PUSH)) {
      nsIFrame* cb = maybeAbsoluteContainingBlock;
      cb->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
      if ((maybeAbsoluteContainingBlockDisplay->IsAbsolutelyPositionedStyle() ||
           maybeAbsoluteContainingBlockDisplay->IsRelativelyPositionedStyle() ||
           (maybeAbsoluteContainingBlockDisplay->HasTransformStyle() &&
            cb->IsFrameOfType(nsIFrame::eSupportsCSSTransforms))) &&
          !cb->IsSVGText()) {
        aState.PushAbsoluteContainingBlock(cb, primaryFrame, absoluteSaveState);
      }
    }

    if (bits & FCDATA_USE_CHILD_ITEMS) {
      NS_ASSERTION(!ShouldSuppressFloatingOfDescendants(newFrame),
                   "uh oh -- this frame is supposed to _suppress_ floats, but "
                   "we're about to push it as a float containing block...");

      nsFrameConstructorSaveState floatSaveState;
      if (newFrame->IsFloatContainingBlock()) {
        aState.PushFloatContainingBlock(newFrame, floatSaveState);
      }
      ConstructFramesFromItemList(aState, aItem.mChildItems, newFrame,
                                  childItems);
    } else {
      // Process the child frames.
      ProcessChildren(aState, content, styleContext, newFrame,
                      !(bits & FCDATA_DISALLOW_GENERATED_CONTENT),
                      childItems,
                      (bits & FCDATA_ALLOW_BLOCK_STYLES) != 0,
                      aItem.mPendingBinding, possiblyLeafFrame);
    }

#ifdef MOZ_XUL
    // More icky XUL stuff
    if (aItem.mNameSpaceID == kNameSpaceID_XUL &&
        (aItem.mTag == nsGkAtoms::treechildren || // trees always need titletips
         content->HasAttr(kNameSpaceID_None, nsGkAtoms::tooltiptext) ||
         content->HasAttr(kNameSpaceID_None, nsGkAtoms::tooltip))) {
      nsIRootBox* rootBox = nsIRootBox::GetRootBox(mPresShell);
      if (rootBox) {
        rootBox->AddTooltipSupport(content);
      }
    }
#endif

    if (bits & FCDATA_WRAP_KIDS_IN_BLOCKS) {
      nsFrameItems newItems;
      nsFrameItems currentBlockItems;
      nsIFrame* f;
      while ((f = childItems.FirstChild()) != nullptr) {
        bool wrapFrame = IsInlineFrame(f) || IsFrameSpecial(f);
        if (!wrapFrame) {
          FlushAccumulatedBlock(aState, content, newFrame,
                                currentBlockItems, newItems);
        }

        childItems.RemoveFrame(f);
        if (wrapFrame) {
          currentBlockItems.AddChild(f);
        } else {
          newItems.AddChild(f);
        }
      }
      FlushAccumulatedBlock(aState, content, newFrame,
                            currentBlockItems, newItems);

      if (childItems.NotEmpty()) {
        // an error must have occurred, delete unprocessed frames
        childItems.DestroyFrames();
      }

      childItems = newItems;
    }

    // Set the frame's initial child list
    // Note that MathML depends on this being called even if
    // childItems is empty!
    newFrame->SetInitialChildList(kPrincipalList, childItems);
  }

  NS_ASSERTION(newFrame->IsFrameOfType(nsIFrame::eLineParticipant) ==
               ((bits & FCDATA_IS_LINE_PARTICIPANT) != 0),
               "Incorrectly set FCDATA_IS_LINE_PARTICIPANT bits");

  // Even if mCreatingExtraFrames is set, we may need to SetPrimaryFrame for
  // generated content that doesn't have one yet.  Note that we have to examine
  // the frame bit, because by this point mIsGeneratedContent has been cleared
  // on aItem.
  if ((!aState.mCreatingExtraFrames ||
       ((primaryFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) &&
        !aItem.mContent->GetPrimaryFrame())) &&
       !(bits & FCDATA_SKIP_FRAMESET)) {
    aItem.mContent->SetPrimaryFrame(primaryFrame);
  }
}

// after the node has been constructed and initialized create any
// anonymous content a node needs.
nsresult
nsCSSFrameConstructor::CreateAnonymousFrames(nsFrameConstructorState& aState,
                                             nsIContent*              aParent,
                                             nsIFrame*                aParentFrame,
                                             PendingBinding*          aPendingBinding,
                                             nsFrameItems&            aChildItems)
{
  nsAutoTArray<nsIAnonymousContentCreator::ContentInfo, 4> newAnonymousItems;
  nsresult rv = GetAnonymousContent(aParent, aParentFrame, newAnonymousItems);
  NS_ENSURE_SUCCESS(rv, rv);

  uint32_t count = newAnonymousItems.Length();
  if (count == 0) {
    return NS_OK;
  }

  nsFrameConstructorState::PendingBindingAutoPusher pusher(aState,
                                                           aPendingBinding);
  TreeMatchContext::AutoAncestorPusher
    ancestorPusher(aState.mTreeMatchContext.mAncestorFilter.HasFilter(),
                   aState.mTreeMatchContext,
                   aParent->AsElement());

  nsIAnonymousContentCreator* creator = do_QueryFrame(aParentFrame);
  NS_ASSERTION(creator,
               "How can that happen if we have nodes to construct frames for?");

  for (uint32_t i=0; i < count; i++) {
    nsIContent* content = newAnonymousItems[i].mContent;
    NS_ASSERTION(content, "null anonymous content?");
    NS_ASSERTION(!newAnonymousItems[i].mStyleContext, "Unexpected style context");

    nsIFrame* newFrame = creator->CreateFrameFor(content);
    if (newFrame) {
      NS_ASSERTION(content->GetPrimaryFrame(),
                   "Content must have a primary frame now");
      aChildItems.AddChild(newFrame);
    }
    else {
      // create the frame and attach it to our frame
      ConstructFrame(aState, content, aParentFrame, aChildItems);
    }
  }

  return NS_OK;
}

static void
SetFlagsOnSubtree(nsIContent *aNode, uintptr_t aFlagsToSet)
{
#ifdef DEBUG
  // Make sure that the node passed to us doesn't have any XBL children
  {
    FlattenedChildIterator iter(aNode);
    NS_ASSERTION(!iter.XBLInvolved() || !iter.GetNextChild(),
                 "The node should not have any XBL children");
  }
#endif

  // Set the flag on the node itself
  aNode->SetFlags(aFlagsToSet);

  // Set the flag on all of its children recursively
  uint32_t count;
  nsIContent * const *children = aNode->GetChildArray(&count);

  for (uint32_t index = 0; index < count; ++index) {
    SetFlagsOnSubtree(children[index], aFlagsToSet);
  }
}

nsresult
nsCSSFrameConstructor::GetAnonymousContent(nsIContent* aParent,
                                           nsIFrame* aParentFrame,
                                           nsTArray<nsIAnonymousContentCreator::ContentInfo>& aContent)
{
  nsIAnonymousContentCreator* creator = do_QueryFrame(aParentFrame);
  if (!creator)
    return NS_OK;

  nsresult rv = creator->CreateAnonymousContent(aContent);
  NS_ENSURE_SUCCESS(rv, rv);

  uint32_t count = aContent.Length();
  for (uint32_t i=0; i < count; i++) {
    // get our child's content and set its parent to our content
    nsIContent* content = aContent[i].mContent;
    NS_ASSERTION(content, "null anonymous content?");

    // least-surprise CSS binding until we do the SVG specified
    // cascading rules for <svg:use> - bug 265894
    if (aParentFrame->GetType() == nsGkAtoms::svgUseFrame) {
      content->SetFlags(NODE_IS_ANONYMOUS);
    } else {
      content->SetNativeAnonymous();
    }

    bool anonContentIsEditable = content->HasFlag(NODE_IS_EDITABLE);
    rv = content->BindToTree(mDocument, aParent, aParent, true);
    // If the anonymous content creator requested that the content should be
    // editable, honor its request.
    // We need to set the flag on the whole subtree, because existing
    // children's flags have already been set as part of the BindToTree operation.
    if (anonContentIsEditable) {
      NS_ASSERTION(aParentFrame->GetType() == nsGkAtoms::textInputFrame,
                   "We only expect this for anonymous content under a text control frame");
      SetFlagsOnSubtree(content, NODE_IS_EDITABLE);
    }
    if (NS_FAILED(rv)) {
      content->UnbindFromTree();
      return rv;
    }
  }

  return NS_OK;
}

static
bool IsXULDisplayType(const nsStyleDisplay* aDisplay)
{
  return (aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_BOX || 
#ifdef MOZ_XUL
          aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_GRID || 
          aDisplay->mDisplay == NS_STYLE_DISPLAY_INLINE_STACK ||
#endif
          aDisplay->mDisplay == NS_STYLE_DISPLAY_BOX
#ifdef MOZ_XUL
          || aDisplay->mDisplay == NS_STYLE_DISPLAY_GRID ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_STACK ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_GRID_GROUP ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_GRID_LINE ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_DECK ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_POPUP ||
          aDisplay->mDisplay == NS_STYLE_DISPLAY_GROUPBOX
#endif
          );
}


// XUL frames are not allowed to be out of flow.
#define SIMPLE_XUL_FCDATA(_func)                                        \
  FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH,    \
              _func)
#define SCROLLABLE_XUL_FCDATA(_func)                                    \
  FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH |   \
              FCDATA_MAY_NEED_SCROLLFRAME, _func)
// .. but we allow some XUL frames to be _containers_ for out-of-flow content
// (This is the same as SCROLLABLE_XUL_FCDATA, but w/o FCDATA_SKIP_ABSPOS_PUSH)
#define SCROLLABLE_ABSPOS_CONTAINER_XUL_FCDATA(_func)                   \
  FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                             \
              FCDATA_MAY_NEED_SCROLLFRAME, _func)

#define SIMPLE_XUL_CREATE(_tag, _func)            \
  { &nsGkAtoms::_tag, SIMPLE_XUL_FCDATA(_func) }
#define SCROLLABLE_XUL_CREATE(_tag, _func)            \
  { &nsGkAtoms::_tag, SCROLLABLE_XUL_FCDATA(_func) }
#define SIMPLE_XUL_INT_CREATE(_int, _func)      \
  { _int, SIMPLE_XUL_FCDATA(_func) }
#define SCROLLABLE_XUL_INT_CREATE(_int, _func)                          \
  { _int, SCROLLABLE_XUL_FCDATA(_func) }
#define SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(_int, _func)         \
  { _int, SCROLLABLE_ABSPOS_CONTAINER_XUL_FCDATA(_func) }

static
nsIFrame* NS_NewGridBoxFrame(nsIPresShell* aPresShell,
                             nsStyleContext* aStyleContext)
{
  nsCOMPtr<nsBoxLayout> layout;
  NS_NewGridLayout2(aPresShell, getter_AddRefs(layout));
  return NS_NewBoxFrame(aPresShell, aStyleContext, false, layout);
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULTagData(Element* aElement,
                                      nsIAtom* aTag,
                                      int32_t aNameSpaceID,
                                      nsStyleContext* aStyleContext)
{
  if (aNameSpaceID != kNameSpaceID_XUL) {
    return nullptr;
  }

  static const FrameConstructionDataByTag sXULTagData[] = {
#ifdef MOZ_XUL
    SCROLLABLE_XUL_CREATE(button, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(checkbox, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(radio, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(autorepeatbutton, NS_NewAutoRepeatBoxFrame),
    SCROLLABLE_XUL_CREATE(titlebar, NS_NewTitleBarFrame),
    SCROLLABLE_XUL_CREATE(resizer, NS_NewResizerFrame),
    SIMPLE_XUL_CREATE(image, NS_NewImageBoxFrame),
    SIMPLE_XUL_CREATE(spring, NS_NewLeafBoxFrame),
    SIMPLE_XUL_CREATE(spacer, NS_NewLeafBoxFrame),
    SIMPLE_XUL_CREATE(treechildren, NS_NewTreeBodyFrame),
    SIMPLE_XUL_CREATE(treecol, NS_NewTreeColFrame),
    SIMPLE_XUL_CREATE(text, NS_NewTextBoxFrame),
    SIMPLE_TAG_CHAIN(label, nsCSSFrameConstructor::FindXULLabelData),
    SIMPLE_TAG_CHAIN(description, nsCSSFrameConstructor::FindXULDescriptionData),
    SIMPLE_XUL_CREATE(menu, NS_NewMenuFrame),
    SIMPLE_XUL_CREATE(menubutton, NS_NewMenuFrame),
    SIMPLE_XUL_CREATE(menuitem, NS_NewMenuItemFrame),
#ifdef XP_MACOSX
    SIMPLE_TAG_CHAIN(menubar, nsCSSFrameConstructor::FindXULMenubarData),
#else
    SIMPLE_XUL_CREATE(menubar, NS_NewMenuBarFrame),
#endif /* XP_MACOSX */
    SIMPLE_TAG_CHAIN(popupgroup, nsCSSFrameConstructor::FindPopupGroupData),
    SIMPLE_XUL_CREATE(iframe, NS_NewSubDocumentFrame),
    SIMPLE_XUL_CREATE(editor, NS_NewSubDocumentFrame),
    SIMPLE_XUL_CREATE(browser, NS_NewSubDocumentFrame),
    SIMPLE_XUL_CREATE(progressmeter, NS_NewProgressMeterFrame),
    SIMPLE_XUL_CREATE(splitter, NS_NewSplitterFrame),
    SIMPLE_TAG_CHAIN(listboxbody,
                     nsCSSFrameConstructor::FindXULListBoxBodyData),
    SIMPLE_TAG_CHAIN(listitem, nsCSSFrameConstructor::FindXULListItemData),
#endif /* MOZ_XUL */
    SIMPLE_XUL_CREATE(slider, NS_NewSliderFrame),
    SIMPLE_XUL_CREATE(scrollbar, NS_NewScrollbarFrame),
    SIMPLE_XUL_CREATE(scrollbarbutton, NS_NewScrollbarButtonFrame)
};

  return FindDataByTag(aTag, aElement, aStyleContext, sXULTagData,
                       ArrayLength(sXULTagData));
}

#ifdef MOZ_XUL
/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindPopupGroupData(Element* aElement,
                                          nsStyleContext* /* unused */)
{
  if (!aElement->IsRootOfNativeAnonymousSubtree()) {
    return nullptr;
  }

  static const FrameConstructionData sPopupSetData =
    SIMPLE_XUL_FCDATA(NS_NewPopupSetFrame);
  return &sPopupSetData;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData
nsCSSFrameConstructor::sXULTextBoxData = SIMPLE_XUL_FCDATA(NS_NewTextBoxFrame);

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULLabelData(Element* aElement,
                                        nsStyleContext* /* unused */)
{
  if (aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
    return &sXULTextBoxData;
  }

  static const FrameConstructionData sLabelData =
    SIMPLE_XUL_FCDATA(NS_NewXULLabelFrame);
  return &sLabelData;
}

static nsIFrame*
NS_NewXULDescriptionFrame(nsIPresShell* aPresShell, nsStyleContext *aContext)
{
  // XXXbz do we really need to set those flags?  If the parent is not
  // a block we'll get them anyway, and if it is, do we want them?
  return NS_NewBlockFrame(aPresShell, aContext,
                          NS_BLOCK_FLOAT_MGR | NS_BLOCK_MARGIN_ROOT);
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULDescriptionData(Element* aElement,
                                              nsStyleContext* /* unused */)
{
  if (aElement->HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
    return &sXULTextBoxData;
  }

  static const FrameConstructionData sDescriptionData =
    SIMPLE_XUL_FCDATA(NS_NewXULDescriptionFrame);
  return &sDescriptionData;
}

#ifdef XP_MACOSX
/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULMenubarData(Element* aElement,
                                          nsStyleContext* aStyleContext)
{
  nsCOMPtr<nsISupports> container =
    aStyleContext->PresContext()->GetContainer();
  if (container) {
    nsCOMPtr<nsIDocShellTreeItem> treeItem(do_QueryInterface(container));
    if (treeItem) {
      int32_t type;
      treeItem->GetItemType(&type);
      if (nsIDocShellTreeItem::typeChrome == type) {
        nsCOMPtr<nsIDocShellTreeItem> parent;
        treeItem->GetParent(getter_AddRefs(parent));
        if (!parent) {
          // This is the root.  Suppress the menubar, since on Mac
          // window menus are not attached to the window.
          static const FrameConstructionData sSuppressData = SUPPRESS_FCDATA();
          return &sSuppressData;
        }
      }
    }
  }

  static const FrameConstructionData sMenubarData =
    SIMPLE_XUL_FCDATA(NS_NewMenuBarFrame);
  return &sMenubarData;
}
#endif /* XP_MACOSX */

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULListBoxBodyData(Element* aElement,
                                              nsStyleContext* aStyleContext)
{
  if (aStyleContext->StyleDisplay()->mDisplay !=
        NS_STYLE_DISPLAY_GRID_GROUP) {
    return nullptr;
  }

  static const FrameConstructionData sListBoxBodyData =
    SCROLLABLE_XUL_FCDATA(NS_NewListBoxBodyFrame);
  return &sListBoxBodyData;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULListItemData(Element* aElement,
                                           nsStyleContext* aStyleContext)
{
  if (aStyleContext->StyleDisplay()->mDisplay !=
        NS_STYLE_DISPLAY_GRID_LINE) {
    return nullptr;
  }

  static const FrameConstructionData sListItemData =
    SCROLLABLE_XUL_FCDATA(NS_NewListItemFrame);
  return &sListItemData;
}

#endif /* MOZ_XUL */

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULDisplayData(const nsStyleDisplay* aDisplay,
                                          Element* aElement,
                                          nsStyleContext* aStyleContext)
{
  static const FrameConstructionDataByInt sXULDisplayData[] = {
    SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_BOX,
                                               NS_NewBoxFrame),
    SCROLLABLE_ABSPOS_CONTAINER_XUL_INT_CREATE(NS_STYLE_DISPLAY_BOX,
                                               NS_NewBoxFrame),
#ifdef MOZ_XUL
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_GRID, NS_NewGridBoxFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_GRID, NS_NewGridBoxFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_GRID_GROUP,
                              NS_NewGridRowGroupFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_GRID_LINE,
                              NS_NewGridRowLeafFrame),
    SIMPLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_DECK, NS_NewDeckFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_GROUPBOX, NS_NewGroupBoxFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_INLINE_STACK, NS_NewStackFrame),
    SCROLLABLE_XUL_INT_CREATE(NS_STYLE_DISPLAY_STACK, NS_NewStackFrame),
    { NS_STYLE_DISPLAY_POPUP,
      FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_IS_POPUP |
                  FCDATA_SKIP_ABSPOS_PUSH, NS_NewMenuPopupFrame) }
#endif /* MOZ_XUL */
  };

  // Processing by display here:
  return FindDataByInt(aDisplay->mDisplay, aElement, aStyleContext,
                       sXULDisplayData, ArrayLength(sXULDisplayData));
}

already_AddRefed<nsStyleContext>
nsCSSFrameConstructor::BeginBuildingScrollFrame(nsFrameConstructorState& aState,
                                                nsIContent*              aContent,
                                                nsStyleContext*          aContentStyle,
                                                nsIFrame*                aParentFrame,
                                                nsIAtom*                 aScrolledPseudo,
                                                bool                     aIsRoot,
                                                nsIFrame*&               aNewFrame)
{
  nsIFrame* gfxScrollFrame = aNewFrame;

  nsFrameItems anonymousItems;

  nsRefPtr<nsStyleContext> contentStyle = aContentStyle;

  if (!gfxScrollFrame) {
    // Build a XULScrollFrame when the child is a box, otherwise an
    // HTMLScrollFrame
    // XXXbz this is the lone remaining consumer of IsXULDisplayType.
    // I wonder whether we can eliminate that somehow.
    const nsStyleDisplay* displayStyle = aContentStyle->StyleDisplay();
    if (IsXULDisplayType(displayStyle)) {
      gfxScrollFrame = NS_NewXULScrollFrame(mPresShell, contentStyle, aIsRoot,
          displayStyle->mDisplay == NS_STYLE_DISPLAY_STACK ||
          displayStyle->mDisplay == NS_STYLE_DISPLAY_INLINE_STACK);
    } else {
      gfxScrollFrame = NS_NewHTMLScrollFrame(mPresShell, contentStyle, aIsRoot);
    }

    InitAndRestoreFrame(aState, aContent, aParentFrame, gfxScrollFrame);
  }

  // if there are any anonymous children for the scroll frame, create
  // frames for them.
  // Pass a null pending binding: we don't care how constructors for any of
  // this anonymous content order with anything else.  It's never been
  // consistent anyway.
  CreateAnonymousFrames(aState, aContent, gfxScrollFrame, nullptr,
                        anonymousItems);

  aNewFrame = gfxScrollFrame;

  // we used the style that was passed in. So resolve another one.
  nsStyleSet *styleSet = mPresShell->StyleSet();
  nsRefPtr<nsStyleContext> scrolledChildStyle =
    styleSet->ResolveAnonymousBoxStyle(aScrolledPseudo, contentStyle);

  if (gfxScrollFrame) {
     gfxScrollFrame->SetInitialChildList(kPrincipalList, anonymousItems);
  }

  return scrolledChildStyle.forget();
}

void
nsCSSFrameConstructor::FinishBuildingScrollFrame(nsIFrame* aScrollFrame,
                                                 nsIFrame* aScrolledFrame)
{
  nsFrameList scrolled(aScrolledFrame, aScrolledFrame);
  aScrollFrame->AppendFrames(kPrincipalList, scrolled);
}


/**
 * Called to wrap a gfx scrollframe around a frame. The hierarchy will look like this
 *
 * ------- for gfx scrollbars ------
 *
 *
 *            ScrollFrame
 *                 ^
 *                 |
 *               Frame (scrolled frame you passed in)
 *
 *
 *-----------------------------------
 * LEGEND:
 * 
 * ScrollFrame: This is a frame that manages gfx cross platform frame based scrollbars.
 *
 * @param aContent the content node of the child to wrap.
 * @param aScrolledFrame The frame of the content to wrap. This should not be
 *                    Initialized. This method will initialize it with a scrolled pseudo
 *                    and no nsIContent. The content will be attached to the scrollframe 
 *                    returned.
 * @param aContentStyle the style context that has already been resolved for the content being passed in.
 *
 * @param aParentFrame The parent to attach the scroll frame to
 *
 * @param aNewFrame The new scrollframe or gfx scrollframe that we create. It will contain the
 *                  scrolled frame you passed in. (returned)
 *                  If this is not null, we'll just use it
 * @param aScrolledContentStyle the style that was resolved for the scrolled frame. (returned)
 */
nsresult
nsCSSFrameConstructor::BuildScrollFrame(nsFrameConstructorState& aState,
                                        nsIContent*              aContent,
                                        nsStyleContext*          aContentStyle,
                                        nsIFrame*                aScrolledFrame,
                                        nsIFrame*                aParentFrame,
                                        nsIFrame*&               aNewFrame)
{
    nsRefPtr<nsStyleContext> scrolledContentStyle =
      BeginBuildingScrollFrame(aState, aContent, aContentStyle, aParentFrame,
                               nsCSSAnonBoxes::scrolledContent,
                               false, aNewFrame);
    
    aScrolledFrame->SetStyleContextWithoutNotification(scrolledContentStyle);
    InitAndRestoreFrame(aState, aContent, aNewFrame, aScrolledFrame);

    FinishBuildingScrollFrame(aNewFrame, aScrolledFrame);
    return NS_OK;
}

const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDisplayData(const nsStyleDisplay* aDisplay,
                                       Element* aElement,
                                       nsIFrame* aParentFrame,
                                       nsStyleContext* aStyleContext)
{
  PR_STATIC_ASSERT(eParentTypeCount < (1 << (32 - FCDATA_PARENT_TYPE_OFFSET)));

  // The style system ensures that floated and positioned frames are
  // block-level.
  NS_ASSERTION(!(aDisplay->IsFloatingStyle() ||
                 aDisplay->IsAbsolutelyPositionedStyle()) ||
               aDisplay->IsBlockOutsideStyle(),
               "Style system did not apply CSS2.1 section 9.7 fixups");

  // If this is "body", try propagating its scroll style to the viewport
  // Note that we need to do this even if the body is NOT scrollable;
  // it might have dynamically changed from scrollable to not scrollable,
  // and that might need to be propagated.
  // XXXbz is this the right place to do this?  If this code moves,
  // make this function static.
  bool propagatedScrollToViewport = false;
  if (aElement->IsHTML(nsGkAtoms::body)) {
    propagatedScrollToViewport =
      PropagateScrollToViewport() == aElement;
  }

  NS_ASSERTION(!propagatedScrollToViewport ||
               !mPresShell->GetPresContext()->IsPaginated(),
               "Shouldn't propagate scroll in paginated contexts");

  // If the frame is a block-level frame and is scrollable, then wrap it in a
  // scroll frame.
  // XXX Ignore tables for the time being
  // XXXbz it would be nice to combine this with the other block
  // case... Think about how do do this?
  if (aDisplay->IsBlockInsideStyle() &&
      aDisplay->IsScrollableOverflow() &&
      !propagatedScrollToViewport) {
    // Except we don't want to do that for paginated contexts for
    // frames that are block-outside and aren't frames for native
    // anonymous stuff.
    if (mPresShell->GetPresContext()->IsPaginated() &&
        aDisplay->IsBlockOutsideStyle() &&
        !aElement->IsInNativeAnonymousSubtree()) {
      static const FrameConstructionData sForcedNonScrollableBlockData =
        FULL_CTOR_FCDATA(FCDATA_FORCED_NON_SCROLLABLE_BLOCK,
                         &nsCSSFrameConstructor::ConstructNonScrollableBlock);
      return &sForcedNonScrollableBlockData;
    }

    static const FrameConstructionData sScrollableBlockData =
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructScrollableBlock);
    return &sScrollableBlockData;
  }

  // Handle various non-scrollable blocks
  if (aDisplay->IsBlockInsideStyle()) {
    static const FrameConstructionData sNonScrollableBlockData =
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructNonScrollableBlock);
    return &sNonScrollableBlockData;
  }

  static const FrameConstructionDataByInt sDisplayData[] = {
    // To keep the hash table small don't add inline frames (they're
    // typically things like FONT and B), because we can quickly
    // find them if we need to.
    // XXXbz the "quickly" part is a bald-faced lie!
    { NS_STYLE_DISPLAY_INLINE,
      FULL_CTOR_FCDATA(FCDATA_IS_INLINE | FCDATA_IS_LINE_PARTICIPANT,
                       &nsCSSFrameConstructor::ConstructInline) },
    { NS_STYLE_DISPLAY_FLEX,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame) },
    { NS_STYLE_DISPLAY_INLINE_FLEX,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame) },
    { NS_STYLE_DISPLAY_TABLE,
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructTable) },
    { NS_STYLE_DISPLAY_INLINE_TABLE,
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructTable) },
    // NOTE: In the unlikely event that we add another table-part here that has
    // a desired-parent-type (& hence triggers table fixup), we'll need to also
    // update the flexbox chunk in nsStyleContext::ApplyStyleFixups().
    { NS_STYLE_DISPLAY_TABLE_CAPTION,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_ALLOW_BLOCK_STYLES |
                  FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableCaptionFrame) },
    { NS_STYLE_DISPLAY_TABLE_ROW_GROUP,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableRowGroupFrame) },
    { NS_STYLE_DISPLAY_TABLE_HEADER_GROUP,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableRowGroupFrame) },
    { NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableRowGroupFrame) },
    { NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableColGroupFrame) },
    { NS_STYLE_DISPLAY_TABLE_COLUMN,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeColGroup),
                       &nsCSSFrameConstructor::ConstructTableCol) },
    { NS_STYLE_DISPLAY_TABLE_ROW,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRowGroup),
                       &nsCSSFrameConstructor::ConstructTableRow) },
    { NS_STYLE_DISPLAY_TABLE_CELL,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRow),
                       &nsCSSFrameConstructor::ConstructTableCell) }
  };

  return FindDataByInt(aDisplay->mDisplay,
                       aElement, aStyleContext, sDisplayData,
                       ArrayLength(sDisplayData));
}

nsIFrame*
nsCSSFrameConstructor::ConstructScrollableBlock(nsFrameConstructorState& aState,
                                                FrameConstructionItem&   aItem,
                                                nsIFrame*                aParentFrame,
                                                const nsStyleDisplay*    aDisplay,
                                                nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;

  nsIFrame* newFrame = nullptr;
  nsRefPtr<nsStyleContext> scrolledContentStyle
    = BeginBuildingScrollFrame(aState, content, styleContext,
                               aState.GetGeometricParent(aDisplay, aParentFrame),
                               nsCSSAnonBoxes::scrolledContent,
                               false, newFrame);

  // Create our block frame
  // pass a temporary stylecontext, the correct one will be set later
  nsIFrame* scrolledFrame =
    NS_NewBlockFormattingContext(mPresShell, styleContext);

  // Make sure to AddChild before we call ConstructBlock so that we
  // end up before our descendants in fixed-pos lists as needed.
  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);

  nsFrameItems blockItem;
  ConstructBlock(aState, scrolledContentStyle->StyleDisplay(), content,
                 newFrame, newFrame, scrolledContentStyle,
                 &scrolledFrame, blockItem,
                 aDisplay->IsPositioned(newFrame) ? newFrame : nullptr,
                 aItem.mPendingBinding);

  NS_ASSERTION(blockItem.FirstChild() == scrolledFrame,
               "Scrollframe's frameItems should be exactly the scrolled frame");
  FinishBuildingScrollFrame(newFrame, scrolledFrame);

  return newFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructNonScrollableBlock(nsFrameConstructorState& aState,
                                                   FrameConstructionItem&   aItem,
                                                   nsIFrame*                aParentFrame,
                                                   const nsStyleDisplay*    aDisplay,
                                                   nsFrameItems&            aFrameItems)
{
  nsStyleContext* const styleContext = aItem.mStyleContext;

  // We want a block formatting context root in paginated contexts for
  // every block that would be scrollable in a non-paginated context.
  // We mark our blocks with a bit here if this condition is true, so
  // we can check it later in nsFrame::ApplyPaginatedOverflowClipping.
  bool clipPaginatedOverflow =
    (aItem.mFCData->mBits & FCDATA_FORCED_NON_SCROLLABLE_BLOCK) != 0;
  nsIFrame* newFrame;
  if ((aDisplay->IsAbsolutelyPositionedStyle() ||
       aDisplay->IsFloatingStyle() ||
       NS_STYLE_DISPLAY_INLINE_BLOCK == aDisplay->mDisplay ||
       clipPaginatedOverflow) &&
      !aParentFrame->IsSVGText()) {
    newFrame = NS_NewBlockFormattingContext(mPresShell, styleContext);
    if (clipPaginatedOverflow) {
      newFrame->AddStateBits(NS_BLOCK_CLIP_PAGINATED_OVERFLOW);
    }
  } else {
    newFrame = NS_NewBlockFrame(mPresShell, styleContext);
  }

  ConstructBlock(aState, aDisplay, aItem.mContent,
                 aState.GetGeometricParent(aDisplay, aParentFrame),
                 aParentFrame, styleContext, &newFrame,
                 aFrameItems,
                 aDisplay->IsPositioned(newFrame) ? newFrame : nullptr,
                 aItem.mPendingBinding);
  return newFrame;
}


void
nsCSSFrameConstructor::InitAndRestoreFrame(const nsFrameConstructorState& aState,
                                           nsIContent*              aContent,
                                           nsIFrame*                aParentFrame,
                                           nsIFrame*                aNewFrame,
                                           bool                     aAllowCounters)
{
  NS_PRECONDITION(mUpdateCount != 0,
                  "Should be in an update while creating frames");
  
  MOZ_ASSERT(aNewFrame, "Null frame cannot be initialized");

  // Initialize the frame
  aNewFrame->Init(aContent, aParentFrame, nullptr);
  aNewFrame->AddStateBits(aState.mAdditionalStateBits);

  if (aState.mFrameState) {
    // Restore frame state for just the newly created frame.
    RestoreFrameStateFor(aNewFrame, aState.mFrameState);
  }

  if (aAllowCounters &&
      mCounterManager.AddCounterResetsAndIncrements(aNewFrame)) {
    CountersDirty();
  }
}

already_AddRefed<nsStyleContext>
nsCSSFrameConstructor::ResolveStyleContext(nsIFrame*         aParentFrame,
                                           nsIContent*       aContent,
                                           nsFrameConstructorState* aState)
{
  nsStyleContext* parentStyleContext = nullptr;
  NS_ASSERTION(aContent->GetParent(), "Must have parent here");

  aParentFrame = nsFrame::CorrectStyleParentFrame(aParentFrame, nullptr);

  if (aParentFrame) {
    // Resolve the style context based on the content object and the parent
    // style context
    parentStyleContext = aParentFrame->StyleContext();
  } else {
    // Perhaps aParentFrame is a canvasFrame and we're replicating
    // fixed-pos frames.
    // XXX should we create a way to tell ConstructFrame which style
    // context to use, and pass it the style context for the
    // previous page's fixed-pos frame?
  }

  return ResolveStyleContext(parentStyleContext, aContent, aState);
}

already_AddRefed<nsStyleContext>
nsCSSFrameConstructor::ResolveStyleContext(nsStyleContext* aParentStyleContext,
                                           nsIContent* aContent,
                                           nsFrameConstructorState* aState)
{
  nsStyleSet *styleSet = mPresShell->StyleSet();
  aContent->OwnerDoc()->FlushPendingLinkUpdates();
  
  if (aContent->IsElement()) {
    if (aState) {
      return styleSet->ResolveStyleFor(aContent->AsElement(),
                                       aParentStyleContext,
                                       aState->mTreeMatchContext);
    }
    return styleSet->ResolveStyleFor(aContent->AsElement(), aParentStyleContext);

  }

  NS_ASSERTION(aContent->IsNodeOfType(nsINode::eTEXT),
               "shouldn't waste time creating style contexts for "
               "comments and processing instructions");

  return styleSet->ResolveStyleForNonElement(aParentStyleContext);
}

// MathML Mod - RBS
void
nsCSSFrameConstructor::FlushAccumulatedBlock(nsFrameConstructorState& aState,
                                             nsIContent* aContent,
                                             nsIFrame* aParentFrame,
                                             nsFrameItems& aBlockItems,
                                             nsFrameItems& aNewItems)
{
  if (aBlockItems.IsEmpty()) {
    // Nothing to do
    return;
  }

  nsIAtom* anonPseudo = nsCSSAnonBoxes::mozMathMLAnonymousBlock;

  nsStyleContext* parentContext =
    nsFrame::CorrectStyleParentFrame(aParentFrame,
                                     anonPseudo)->StyleContext();
  nsStyleSet* styleSet = mPresShell->StyleSet();
  nsRefPtr<nsStyleContext> blockContext;
  blockContext = styleSet->
    ResolveAnonymousBoxStyle(anonPseudo, parentContext);


  // then, create a block frame that will wrap the child frames. Make it a
  // MathML frame so that Get(Absolute/Float)ContainingBlockFor know that this
  // is not a suitable block.
  nsIFrame* blockFrame =
      NS_NewMathMLmathBlockFrame(mPresShell, blockContext,
                                 NS_BLOCK_FLOAT_MGR | NS_BLOCK_MARGIN_ROOT);

  InitAndRestoreFrame(aState, aContent, aParentFrame, blockFrame);
  ReparentFrames(this, blockFrame, aBlockItems);
  // abs-pos and floats are disabled in MathML children so we don't have to
  // worry about messing up those.
  blockFrame->SetInitialChildList(kPrincipalList, aBlockItems);
  NS_ASSERTION(aBlockItems.IsEmpty(), "What happened?");
  aBlockItems.Clear();
  aNewItems.AddChild(blockFrame);
}

// Only <math> elements can be floated or positioned.  All other MathML
// should be in-flow.
#define SIMPLE_MATHML_CREATE(_tag, _func)                               \
  { &nsGkAtoms::_tag,                                                   \
      FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                         \
                  FCDATA_FORCE_NULL_ABSPOS_CONTAINER |                  \
                  FCDATA_WRAP_KIDS_IN_BLOCKS, _func) }

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindMathMLData(Element* aElement,
                                      nsIAtom* aTag,
                                      int32_t aNameSpaceID,
                                      nsStyleContext* aStyleContext)
{
  // Make sure that we remain confined in the MathML world
  if (aNameSpaceID != kNameSpaceID_MathML) 
    return nullptr;

  // Handle <math> specially, because it sometimes produces inlines
  if (aTag == nsGkAtoms::math) {
    // This needs to match the test in EnsureBlockDisplay in
    // nsRuleNode.cpp.  Though the behavior here for the display:table
    // case is pretty weird...
    if (aStyleContext->StyleDisplay()->IsBlockOutsideStyle()) {
      static const FrameConstructionData sBlockMathData =
        FCDATA_DECL(FCDATA_FORCE_NULL_ABSPOS_CONTAINER |
                    FCDATA_WRAP_KIDS_IN_BLOCKS,
                    NS_CreateNewMathMLmathBlockFrame);
      return &sBlockMathData;
    }

    static const FrameConstructionData sInlineMathData =
      FCDATA_DECL(FCDATA_FORCE_NULL_ABSPOS_CONTAINER |
                  FCDATA_IS_LINE_PARTICIPANT |
                  FCDATA_WRAP_KIDS_IN_BLOCKS,
                  NS_NewMathMLmathInlineFrame);
    return &sInlineMathData;
  }
      

  static const FrameConstructionDataByTag sMathMLData[] = {
    SIMPLE_MATHML_CREATE(annotation_, NS_NewMathMLTokenFrame),
    SIMPLE_MATHML_CREATE(annotation_xml_, NS_NewMathMLmrowFrame),
    SIMPLE_MATHML_CREATE(mi_, NS_NewMathMLTokenFrame),
    SIMPLE_MATHML_CREATE(mn_, NS_NewMathMLTokenFrame),
    SIMPLE_MATHML_CREATE(ms_, NS_NewMathMLTokenFrame),
    SIMPLE_MATHML_CREATE(mtext_, NS_NewMathMLTokenFrame),
    SIMPLE_MATHML_CREATE(mo_, NS_NewMathMLmoFrame),
    SIMPLE_MATHML_CREATE(mfrac_, NS_NewMathMLmfracFrame),
    SIMPLE_MATHML_CREATE(msup_, NS_NewMathMLmsupFrame),
    SIMPLE_MATHML_CREATE(msub_, NS_NewMathMLmsubFrame),
    SIMPLE_MATHML_CREATE(msubsup_, NS_NewMathMLmsubsupFrame),
    SIMPLE_MATHML_CREATE(munder_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(mover_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(munderover_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(mphantom_, NS_NewMathMLmphantomFrame),
    SIMPLE_MATHML_CREATE(mpadded_, NS_NewMathMLmpaddedFrame),
    SIMPLE_MATHML_CREATE(mspace_, NS_NewMathMLmspaceFrame),
    SIMPLE_MATHML_CREATE(none, NS_NewMathMLmspaceFrame),
    SIMPLE_MATHML_CREATE(mprescripts_, NS_NewMathMLmspaceFrame),
    SIMPLE_MATHML_CREATE(mfenced_, NS_NewMathMLmfencedFrame),
    SIMPLE_MATHML_CREATE(mmultiscripts_, NS_NewMathMLmmultiscriptsFrame),
    SIMPLE_MATHML_CREATE(mstyle_, NS_NewMathMLmstyleFrame),
    SIMPLE_MATHML_CREATE(msqrt_, NS_NewMathMLmsqrtFrame),
    SIMPLE_MATHML_CREATE(mroot_, NS_NewMathMLmrootFrame),
    SIMPLE_MATHML_CREATE(maction_, NS_NewMathMLmactionFrame),
    SIMPLE_MATHML_CREATE(mrow_, NS_NewMathMLmrowFrame),
    SIMPLE_MATHML_CREATE(merror_, NS_NewMathMLmrowFrame),
    SIMPLE_MATHML_CREATE(menclose_, NS_NewMathMLmencloseFrame),
    SIMPLE_MATHML_CREATE(semantics_, NS_NewMathMLsemanticsFrame)
  };

  return FindDataByTag(aTag, aElement, aStyleContext, sMathMLData,
                       ArrayLength(sMathMLData));
}


// Construct an nsSVGOuterSVGFrame, the anonymous child that wraps its real
// children, and its descendant frames.
nsIFrame*
nsCSSFrameConstructor::ConstructOuterSVG(nsFrameConstructorState& aState,
                                         FrameConstructionItem&   aItem,
                                         nsIFrame*                aParentFrame,
                                         const nsStyleDisplay*    aDisplay,
                                         nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  nsStyleContext* const styleContext = aItem.mStyleContext;

  // Create the nsSVGOuterSVGFrame:
  nsIFrame* newFrame = NS_NewSVGOuterSVGFrame(mPresShell, styleContext);

  nsIFrame* geometricParent =
    aState.GetGeometricParent(styleContext->StyleDisplay(),
                              aParentFrame);

  InitAndRestoreFrame(aState, content, geometricParent, newFrame);

  // Create the pseudo SC for the anonymous wrapper child as a child of the SC:
  nsRefPtr<nsStyleContext> scForAnon;
  scForAnon = mPresShell->StyleSet()->
    ResolveAnonymousBoxStyle(nsCSSAnonBoxes::mozSVGOuterSVGAnonChild,
                             styleContext);

  // Create the anonymous inner wrapper frame
  nsIFrame* innerFrame = NS_NewSVGOuterSVGAnonChildFrame(mPresShell, scForAnon);

  InitAndRestoreFrame(aState, content, newFrame, innerFrame);

  // Put the newly created frames into the right child list
  SetInitialSingleChild(newFrame, innerFrame);

  aState.AddChild(newFrame, aFrameItems, content, styleContext, aParentFrame);

  if (!mRootElementFrame) {
    // The frame we're constructing will be the root element frame.
    // Set mRootElementFrame before processing children.
    mRootElementFrame = newFrame;
  }

  nsFrameItems childItems;

  // Process children
  if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
    ConstructFramesFromItemList(aState, aItem.mChildItems,
                                innerFrame, childItems);
  } else {
    ProcessChildren(aState, content, styleContext, innerFrame,
                    true, childItems, false, aItem.mPendingBinding);
  }

  // Set the inner wrapper frame's initial primary list
  innerFrame->SetInitialChildList(kPrincipalList, childItems);

  return newFrame;
}

// Only outer <svg> elements can be floated or positioned.  All other SVG
// should be in-flow.
#define SIMPLE_SVG_FCDATA(_func)                                        \
  FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |                             \
              FCDATA_SKIP_ABSPOS_PUSH |                                 \
              FCDATA_DISALLOW_GENERATED_CONTENT,  _func)
#define SIMPLE_SVG_CREATE(_tag, _func)            \
  { &nsGkAtoms::_tag, SIMPLE_SVG_FCDATA(_func) }

static bool
IsFilterPrimitiveChildTag(const nsIAtom* aTag)
{
  return aTag == nsGkAtoms::feDistantLight ||
         aTag == nsGkAtoms::fePointLight ||
         aTag == nsGkAtoms::feSpotLight ||
         aTag == nsGkAtoms::feFuncR ||
         aTag == nsGkAtoms::feFuncG ||
         aTag == nsGkAtoms::feFuncB ||
         aTag == nsGkAtoms::feFuncA ||
         aTag == nsGkAtoms::feMergeNode;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindSVGData(Element* aElement,
                                   nsIAtom* aTag,
                                   int32_t aNameSpaceID,
                                   nsIFrame* aParentFrame,
                                   bool aIsWithinSVGText,
                                   bool aAllowsTextPathChild,
                                   nsStyleContext* aStyleContext)
{
  if (aNameSpaceID != kNameSpaceID_SVG) {
    return nullptr;
  }

  static const FrameConstructionData sSuppressData = SUPPRESS_FCDATA();
  static const FrameConstructionData sContainerData =
    SIMPLE_SVG_FCDATA(NS_NewSVGContainerFrame);

  bool parentIsSVG = aIsWithinSVGText;
  nsIContent* parentContent =
    aParentFrame ? aParentFrame->GetContent() : nullptr;
  // XXXbz should this really be based on the XBL-resolved tag of the parent
  // frame's content?  Should it not be based on the type of the parent frame
  // (e.g. whether it's an SVG frame)?
  if (parentContent) {
    int32_t parentNSID;
    nsIAtom* parentTag =
      parentContent->OwnerDoc()->BindingManager()->
        ResolveTag(parentContent, &parentNSID);

    // It's not clear whether the SVG spec intends to allow any SVG
    // content within svg:foreignObject at all (SVG 1.1, section
    // 23.2), but if it does, it better be svg:svg.  So given that
    // we're allowing it, treat it as a non-SVG parent.
    parentIsSVG = parentNSID == kNameSpaceID_SVG &&
                  parentTag != nsGkAtoms::foreignObject;
  }

  if ((aTag != nsGkAtoms::svg && !parentIsSVG) ||
      (aTag == nsGkAtoms::desc || aTag == nsGkAtoms::title)) {
    // Sections 5.1 and G.4 of SVG 1.1 say that SVG elements other than
    // svg:svg not contained within svg:svg are incorrect, although they
    // don't seem to specify error handling.  Ignore them, since many of
    // our frame classes can't deal.  It *may* be that the document
    // should at that point be considered in error according to F.2, but
    // it's hard to tell.
    //
    // Style mutation can't change this situation, so don't bother
    // adding to the undisplayed content map.
    //
    // We don't currently handle any UI for desc/title
    return &sSuppressData;
  }

  // We don't need frames for animation elements
  if (aElement->IsNodeOfType(nsINode::eANIMATION)) {
    return &sSuppressData;
  }

  if (aTag == nsGkAtoms::svg && !parentIsSVG) {
    // We need outer <svg> elements to have an nsSVGOuterSVGFrame regardless
    // of whether they fail conditional processing attributes, since various
    // SVG frames assume that one exists.  We handle the non-rendering
    // of failing outer <svg> element contents like <switch> statements,
    // and do the PassesConditionalProcessingTests call in
    // nsSVGOuterSVGFrame::Init.
    static const FrameConstructionData sOuterSVGData =
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructOuterSVG);
    return &sOuterSVGData;
  }

  nsCOMPtr<SVGTests> tests(do_QueryInterface(aElement));
  if (tests && !tests->PassesConditionalProcessingTests()) {
    // Elements with failing conditional processing attributes never get
    // rendered.  Note that this is not where we select which frame in a
    // <switch> to render!  That happens in nsSVGSwitchFrame::PaintSVG.
    return &sContainerData;
  }

  // Prevent bad frame types being children of filters or parents of filter
  // primitives.  If aParentFrame is null, we know that the frame that will
  // be created will be an nsInlineFrame, so it can never be a filter.
  bool parentIsFilter = aParentFrame &&
    aParentFrame->GetType() == nsGkAtoms::svgFilterFrame;
  bool filterPrimitive = aElement->IsNodeOfType(nsINode::eFILTER);
  if ((parentIsFilter && !filterPrimitive) ||
      (!parentIsFilter && filterPrimitive)) {
    return &sSuppressData;
  }

  // Prevent bad frame types being children of filter primitives or parents of
  // filter primitive children.  If aParentFrame is null, we know that the frame
  // that will be created will be an nsInlineFrame, so it can never be a filter
  // primitive.
  bool parentIsFEContainerFrame = aParentFrame &&
    aParentFrame->GetType() == nsGkAtoms::svgFEContainerFrame;
  if ((parentIsFEContainerFrame && !IsFilterPrimitiveChildTag(aTag)) ||
      (!parentIsFEContainerFrame && IsFilterPrimitiveChildTag(aTag))) {
    return &sSuppressData;
  }

  // Special cases for text/tspan/textPath, because the kind of frame
  // they get depends on the parent frame.  We ignore 'a' elements when
  // determining the parent, however.
  if (aIsWithinSVGText) {
    // If aIsWithinSVGText is true, then we know that the "SVG text uses
    // CSS frames" pref was true when this SVG fragment was first constructed.

    // We don't use ConstructInline because we want different behavior
    // for generated content.
    static const FrameConstructionData sTSpanData =
      FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DISALLOW_GENERATED_CONTENT |
                  FCDATA_IS_LINE_PARTICIPANT |
                  FCDATA_IS_INLINE |
                  FCDATA_USE_CHILD_ITEMS,
                  NS_NewInlineFrame);
    if (aTag == nsGkAtoms::textPath) {
      if (aAllowsTextPathChild) {
        return &sTSpanData;
      }
    } else if (aTag == nsGkAtoms::tspan ||
               aTag == nsGkAtoms::altGlyph ||
               aTag == nsGkAtoms::a) {
      return &sTSpanData;
    }
    return &sSuppressData;
  } else if (NS_SVGTextCSSFramesEnabled()) {
    if (aTag == nsGkAtoms::text) {
      static const FrameConstructionData sTextData =
        FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW |
                                   FCDATA_ALLOW_BLOCK_STYLES,
                                   NS_NewSVGTextFrame2,
                                   nsCSSAnonBoxes::mozSVGText);
      return &sTextData;
    } else if (aTag == nsGkAtoms::tspan ||
               aTag == nsGkAtoms::altGlyph ||
               aTag == nsGkAtoms::textPath) {
      return &sSuppressData;
    }
  } else {
    nsIFrame *ancestorFrame =
      nsSVGUtils::GetFirstNonAAncestorFrame(aParentFrame);
    if (ancestorFrame) {
      if (aTag == nsGkAtoms::tspan || aTag == nsGkAtoms::altGlyph) {
        // tspan and altGlyph must be children of another text content element.
        nsSVGTextContainerFrame* metrics = do_QueryFrame(ancestorFrame);
        if (!metrics) {
          return &sSuppressData;
        }
      } else if (aTag == nsGkAtoms::textPath) {
        // textPath must be a child of text.
        nsIAtom* ancestorFrameType = ancestorFrame->GetType();
        if (ancestorFrameType != nsGkAtoms::svgTextFrame) {
          return &sSuppressData;
        }
      } else if (aTag != nsGkAtoms::a) {
        // Every other element except 'a' must not be a child of a text content
        // element.
        nsSVGTextContainerFrame* metrics = do_QueryFrame(ancestorFrame);
        if (metrics) {
          return &sSuppressData;
        }
      }
    }
  }

  static const FrameConstructionDataByTag sSVGData[] = {
    SIMPLE_SVG_CREATE(svg, NS_NewSVGInnerSVGFrame),
    SIMPLE_SVG_CREATE(g, NS_NewSVGGFrame),
    SIMPLE_SVG_CREATE(svgSwitch, NS_NewSVGSwitchFrame),
    SIMPLE_SVG_CREATE(polygon, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(polyline, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(circle, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(ellipse, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(line, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(rect, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(path, NS_NewSVGPathGeometryFrame),
    SIMPLE_SVG_CREATE(defs, NS_NewSVGContainerFrame),
    SIMPLE_SVG_CREATE(generic_, NS_NewSVGGenericContainerFrame),
    { &nsGkAtoms::foreignObject,
      FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW,
                                 NS_NewSVGForeignObjectFrame,
                                 nsCSSAnonBoxes::mozSVGForeignContent) },
    SIMPLE_SVG_CREATE(a, NS_NewSVGAFrame),
    SIMPLE_SVG_CREATE(altGlyph, NS_NewSVGTSpanFrame),
    SIMPLE_SVG_CREATE(text, NS_NewSVGTextFrame),
    SIMPLE_SVG_CREATE(tspan, NS_NewSVGTSpanFrame),
    SIMPLE_SVG_CREATE(linearGradient, NS_NewSVGLinearGradientFrame),
    SIMPLE_SVG_CREATE(radialGradient, NS_NewSVGRadialGradientFrame),
    SIMPLE_SVG_CREATE(stop, NS_NewSVGStopFrame),
    SIMPLE_SVG_CREATE(use, NS_NewSVGUseFrame),
    SIMPLE_SVG_CREATE(view, NS_NewSVGViewFrame),
    SIMPLE_SVG_CREATE(marker, NS_NewSVGMarkerFrame),
    SIMPLE_SVG_CREATE(image, NS_NewSVGImageFrame),
    SIMPLE_SVG_CREATE(clipPath, NS_NewSVGClipPathFrame),
    SIMPLE_SVG_CREATE(textPath, NS_NewSVGTextPathFrame),
    SIMPLE_SVG_CREATE(filter, NS_NewSVGFilterFrame),
    SIMPLE_SVG_CREATE(pattern, NS_NewSVGPatternFrame),
    SIMPLE_SVG_CREATE(mask, NS_NewSVGMaskFrame),
    SIMPLE_SVG_CREATE(feDistantLight, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(fePointLight, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feSpotLight, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feBlend, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feColorMatrix, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feFuncR, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feFuncG, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feFuncB, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feFuncA, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feComposite, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feComponentTransfer, NS_NewSVGFEContainerFrame),
    SIMPLE_SVG_CREATE(feConvolveMatrix, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feDiffuseLighting, NS_NewSVGFEContainerFrame),
    SIMPLE_SVG_CREATE(feDisplacementMap, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feFlood, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feGaussianBlur, NS_NewSVGFELeafFrame),
    SIMPLE_SVG_CREATE(feImage, NS_NewSVGFEImageFrame),
    SIMPLE_SVG_CREATE(feMerge, NS_NewSVGFEContainerFrame),
    SIMPLE_SVG_CREATE(feMergeNode, NS_NewSVGFEUnstyledLeafFrame),
    SIMPLE_SVG_CREATE(feMorphology, NS_NewSVGFELeafFrame), 
    SIMPLE_SVG_CREATE(feOffset, NS_NewSVGFELeafFrame), 
    SIMPLE_SVG_CREATE(feSpecularLighting, NS_NewSVGFEContainerFrame),
    SIMPLE_SVG_CREATE(feTile, NS_NewSVGFELeafFrame), 
    SIMPLE_SVG_CREATE(feTurbulence, NS_NewSVGFELeafFrame) 
  };

  const FrameConstructionData* data =
    FindDataByTag(aTag, aElement, aStyleContext, sSVGData,
                  ArrayLength(sSVGData));

  if (!data) {
    data = &sContainerData;
  }

  return data;
}

void
nsCSSFrameConstructor::AddPageBreakItem(nsIContent* aContent,
                                        nsStyleContext* aMainStyleContext,
                                        FrameConstructionItemList& aItems)
{
  nsRefPtr<nsStyleContext> pseudoStyle;
  // Use the same parent style context that |aMainStyleContext| has, since
  // that's easier to re-resolve and it doesn't matter in practice.
  // (Getting different parents can result in framechange hints, e.g.,
  // for user-modify.)
  pseudoStyle =
    mPresShell->StyleSet()->
      ResolveAnonymousBoxStyle(nsCSSAnonBoxes::pageBreak,
                               aMainStyleContext->GetParent());

  NS_ASSERTION(pseudoStyle->StyleDisplay()->mDisplay ==
                 NS_STYLE_DISPLAY_BLOCK, "Unexpected display");

  static const FrameConstructionData sPageBreakData =
    FCDATA_DECL(FCDATA_SKIP_FRAMESET, NS_NewPageBreakFrame);

  // Lie about the tag and namespace so we don't trigger anything
  // interesting during frame construction.
  aItems.AppendItem(&sPageBreakData, aContent, nsCSSAnonBoxes::pageBreak,
                    kNameSpaceID_None, nullptr, pseudoStyle.forget(), true);
}

void
nsCSSFrameConstructor::ConstructFrame(nsFrameConstructorState& aState,
                                      nsIContent*              aContent,
                                      nsIFrame*                aParentFrame,
                                      nsFrameItems&            aFrameItems)

{
  NS_PRECONDITION(aParentFrame, "no parent frame");
  // NOTE: If we start using this code for non-anonymous content, we'll need
  // to evaluate whether the AutoFlexItemStyleFixupSkipper (instantiated below)
  // is appropriate for that content.
  NS_PRECONDITION(aContent->IsRootOfNativeAnonymousSubtree(),
                  "ConstructFrame should only be used for anonymous content");

  FrameConstructionItemList items;
  {
    // Skip flex item style-fixup during our AddFrameConstructionItems() call:
    TreeMatchContext::AutoFlexItemStyleFixupSkipper
      flexItemStyleFixupSkipper(aState.mTreeMatchContext);

    AddFrameConstructionItems(aState, aContent, true, aParentFrame, items);
  }
  items.SetTriedConstructingFrames();

  for (FCItemIterator iter(items); !iter.IsDone(); iter.Next()) {
    NS_ASSERTION(iter.item().DesiredParentType() == GetParentType(aParentFrame),
                 "This is not going to work");
    ConstructFramesFromItem(aState, iter, aParentFrame, aFrameItems);
  }
}

void
nsCSSFrameConstructor::AddFrameConstructionItems(nsFrameConstructorState& aState,
                                                 nsIContent* aContent,
                                                 bool aSuppressWhiteSpaceOptimizations,
                                                 nsIFrame* aParentFrame,
                                                 FrameConstructionItemList& aItems)
{
  aContent->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
  if (aContent->IsElement()) {
    // We can't just remove our pending restyle flags, since we may
    // have restyle-later-siblings set on us.  But we _can_ remove the
    // "is possible restyle root" flags, and need to.  Otherwise we can
    // end up with stale such flags (e.g. if we used to have a
    // display:none parent when our last restyle was posted and
    // processed and now no longer do).
    aContent->UnsetFlags(ELEMENT_ALL_RESTYLE_FLAGS &
                         ~ELEMENT_PENDING_RESTYLE_FLAGS);
  }

  // XXX the GetContent() != aContent check is needed due to bug 135040.
  // Remove it once that's fixed.  
  if (aContent->GetPrimaryFrame() &&
      aContent->GetPrimaryFrame()->GetContent() == aContent &&
      !aState.mCreatingExtraFrames) {
    NS_ERROR("asked to create frame construction item for a node that already "
             "has a frame");
    return;
  }

  // don't create a whitespace frame if aParent doesn't want it
  if (!NeedFrameFor(aState, aParentFrame, aContent)) {
    return;
  }

  // never create frames for comments or PIs
  if (aContent->IsNodeOfType(nsINode::eCOMMENT) ||
      aContent->IsNodeOfType(nsINode::ePROCESSING_INSTRUCTION))
    return;

  nsRefPtr<nsStyleContext> styleContext;
  styleContext = ResolveStyleContext(aParentFrame, aContent, &aState);

  uint32_t flags = ITEM_ALLOW_XBL_BASE | ITEM_ALLOW_PAGE_BREAK;
  if (aParentFrame->IsSVGText()) {
    flags |= ITEM_IS_WITHIN_SVG_TEXT;
  }
  if (aParentFrame->GetType() == nsGkAtoms::blockFrame &&
      aParentFrame->GetParent() &&
      aParentFrame->GetParent()->GetType() == nsGkAtoms::svgTextFrame2) {
    flags |= ITEM_ALLOWS_TEXT_PATH_CHILD;
  }
  AddFrameConstructionItemsInternal(aState, aContent, aParentFrame,
                                    aContent->Tag(), aContent->GetNameSpaceID(),
                                    aSuppressWhiteSpaceOptimizations,
                                    styleContext,
                                    flags,
                                    aItems);
}

/* static */ void
nsCSSFrameConstructor::SetAsUndisplayedContent(FrameConstructionItemList& aList,
                                               nsIContent* aContent,
                                               nsStyleContext* aStyleContext,
                                               bool aIsGeneratedContent)
{
  if (aStyleContext->GetPseudo()) {
    if (aIsGeneratedContent) {
      aContent->UnbindFromTree();
    }
    return;
  }

  NS_ASSERTION(!aIsGeneratedContent, "Should have had pseudo type");
  aList.AppendUndisplayedItem(aContent, aStyleContext);
}

void
nsCSSFrameConstructor::AddFrameConstructionItemsInternal(nsFrameConstructorState& aState,
                                                         nsIContent* aContent,
                                                         nsIFrame* aParentFrame,
                                                         nsIAtom* aTag,
                                                         int32_t aNameSpaceID,
                                                         bool aSuppressWhiteSpaceOptimizations,
                                                         nsStyleContext* aStyleContext,
                                                         uint32_t aFlags,
                                                         FrameConstructionItemList& aItems)
{
  NS_PRECONDITION(aContent->IsNodeOfType(nsINode::eTEXT) ||
                  aContent->IsElement(),
                  "Shouldn't get anything else here!");

  // The following code allows the user to specify the base tag
  // of an element using XBL.  XUL and HTML objects (like boxes, menus, etc.)
  // can then be extended arbitrarily.
  const nsStyleDisplay* display = aStyleContext->StyleDisplay();
  nsRefPtr<nsStyleContext> styleContext(aStyleContext);
  PendingBinding* pendingBinding = nullptr;
  if ((aFlags & ITEM_ALLOW_XBL_BASE) && display->mBinding)
  {
    // Ensure that our XBL bindings are installed.

    nsXBLService* xblService = nsXBLService::GetInstance();
    if (!xblService)
      return;

    bool resolveStyle;

    nsAutoPtr<PendingBinding> newPendingBinding(new PendingBinding());

    nsresult rv = xblService->LoadBindings(aContent, display->mBinding->GetURI(),
                                           display->mBinding->mOriginPrincipal,
                                           getter_AddRefs(newPendingBinding->mBinding),
                                           &resolveStyle);
    if (NS_FAILED(rv) && rv != NS_ERROR_XBL_BLOCKED)
      return;

    if (newPendingBinding->mBinding) {
      pendingBinding = newPendingBinding;
      // aState takes over owning newPendingBinding
      aState.AddPendingBinding(newPendingBinding.forget());
    }

    if (resolveStyle) {
      styleContext =
        ResolveStyleContext(styleContext->GetParent(), aContent, &aState);
      display = styleContext->StyleDisplay();
      aStyleContext = styleContext;
    }

    aTag = mDocument->BindingManager()->ResolveTag(aContent, &aNameSpaceID);
  }

  bool isGeneratedContent = ((aFlags & ITEM_IS_GENERATED_CONTENT) != 0);

  // Pre-check for display "none" - if we find that, don't create
  // any frame at all
  if (NS_STYLE_DISPLAY_NONE == display->mDisplay) {
    SetAsUndisplayedContent(aItems, aContent, styleContext, isGeneratedContent);
    return;
  }

  bool isText = !aContent->IsElement();

  // never create frames for non-option/optgroup kids of <select> and
  // non-option kids of <optgroup> inside a <select>.
  // XXXbz it's not clear how this should best work with XBL.
  nsIContent *parent = aContent->GetParent();
  if (parent) {
    // Check tag first, since that check will usually fail
    nsIAtom* parentTag = parent->Tag();
    if ((parentTag == nsGkAtoms::select || parentTag == nsGkAtoms::optgroup) &&
        parent->IsHTML() &&
        // <option> is ok no matter what
        !aContent->IsHTML(nsGkAtoms::option) &&
        // <optgroup> is OK in <select> but not in <optgroup>
        (!aContent->IsHTML(nsGkAtoms::optgroup) ||
         parentTag != nsGkAtoms::select) &&
        // Allow native anonymous content no matter what
        !aContent->IsRootOfNativeAnonymousSubtree()) {
      // No frame for aContent
      if (!isText) {
        SetAsUndisplayedContent(aItems, aContent, styleContext,
                                isGeneratedContent);
      }
      return;
    }
  }

  bool isPopup = false;
  // Try to find frame construction data for this content
  const FrameConstructionData* data;
  if (isText) {
    data = FindTextData(aParentFrame);
    if (!data) {
      // Nothing to do here; suppressed text inside SVG
      return;
    }
  } else {
    Element* element = aContent->AsElement();

    // Don't create frames for non-SVG element children of SVG elements.
    if (aNameSpaceID != kNameSpaceID_SVG &&
        ((aParentFrame &&
          IsFrameForSVG(aParentFrame) &&
          !aParentFrame->IsFrameOfType(nsIFrame::eSVGForeignObject)) ||
         (aFlags & ITEM_IS_WITHIN_SVG_TEXT))) {
      SetAsUndisplayedContent(aItems, element, styleContext,
                              isGeneratedContent);
      return;
    }

    data = FindHTMLData(element, aTag, aNameSpaceID, aParentFrame,
                        styleContext);
    if (!data) {
      data = FindXULTagData(element, aTag, aNameSpaceID, styleContext);
    }
    if (!data) {
      data = FindMathMLData(element, aTag, aNameSpaceID, styleContext);
    }
    if (!data) {
      data = FindSVGData(element, aTag, aNameSpaceID, aParentFrame,
                         aFlags & ITEM_IS_WITHIN_SVG_TEXT,
                         aFlags & ITEM_ALLOWS_TEXT_PATH_CHILD,
                         styleContext);
    }

    // Now check for XUL display types
    if (!data) {
      data = FindXULDisplayData(display, element, styleContext);
    }

    // And general display types
    if (!data) {
      data = FindDisplayData(display, element, aParentFrame, styleContext);
    }

    NS_ASSERTION(data, "Should have frame construction data now");

    if (data->mBits & FCDATA_SUPPRESS_FRAME) {
      SetAsUndisplayedContent(aItems, element, styleContext, isGeneratedContent);
      return;
    }

#ifdef MOZ_XUL
    if ((data->mBits & FCDATA_IS_POPUP) &&
        (!aParentFrame || // Parent is inline
         aParentFrame->GetType() != nsGkAtoms::menuFrame)) {
      if (!aState.mPopupItems.containingBlock &&
          !aState.mHavePendingPopupgroup) {
        SetAsUndisplayedContent(aItems, element, styleContext,
                                isGeneratedContent);
        return;
      }

      isPopup = true;
    }
#endif /* MOZ_XUL */
  }

  uint32_t bits = data->mBits;

  // Inside colgroups, suppress everything except columns.
  if (aParentFrame &&
      aParentFrame->GetType() == nsGkAtoms::tableColGroupFrame &&
      (!(bits & FCDATA_IS_TABLE_PART) ||
       display->mDisplay != NS_STYLE_DISPLAY_TABLE_COLUMN)) {
    SetAsUndisplayedContent(aItems, aContent, styleContext, isGeneratedContent);
    return;
  }

  bool canHavePageBreak =
    (aFlags & ITEM_ALLOW_PAGE_BREAK) &&
    aState.mPresContext->IsPaginated() &&
    !display->IsAbsolutelyPositionedStyle() &&
    !(bits & FCDATA_IS_TABLE_PART) &&
    !(bits & FCDATA_IS_SVG_TEXT);

  if (canHavePageBreak && display->mBreakBefore) {
    AddPageBreakItem(aContent, aStyleContext, aItems);
  }

  FrameConstructionItem* item =
    aItems.AppendItem(data, aContent, aTag, aNameSpaceID,
                      pendingBinding, styleContext.forget(),
                      aSuppressWhiteSpaceOptimizations);
  if (!item) {
    if (isGeneratedContent) {
      aContent->UnbindFromTree();
    }
    return;
  }

  item->mIsText = isText;
  item->mIsGeneratedContent = isGeneratedContent;
  if (isGeneratedContent) {
    NS_ADDREF(item->mContent);
  }
  item->mIsRootPopupgroup =
    aNameSpaceID == kNameSpaceID_XUL && aTag == nsGkAtoms::popupgroup &&
    aContent->IsRootOfNativeAnonymousSubtree();
  if (item->mIsRootPopupgroup) {
    aState.mHavePendingPopupgroup = true;
  }
  item->mIsPopup = isPopup;
  item->mIsForSVGAElement = aNameSpaceID == kNameSpaceID_SVG &&
                            aTag == nsGkAtoms::a;

  if (canHavePageBreak && display->mBreakAfter) {
    AddPageBreakItem(aContent, aStyleContext, aItems);
  }

  if (bits & FCDATA_IS_INLINE) {
    // To correctly set item->mIsAllInline we need to build up our child items
    // right now.
    BuildInlineChildItems(aState, *item,
                          aFlags & ITEM_IS_WITHIN_SVG_TEXT,
                          aFlags & ITEM_ALLOWS_TEXT_PATH_CHILD);
    item->mHasInlineEnds = true;
    item->mIsBlock = false;
  } else {
    // Compute a boolean isInline which is guaranteed to be false for blocks
    // (but may also be false for some inlines).
    bool isInline =
      // Table-internal things are inline-outside if and only if they're kids of
      // inlines, since they'll trigger construction of inline-table
      // pseudos.
      ((bits & FCDATA_IS_TABLE_PART) &&
       (!aParentFrame || // No aParentFrame means inline
        aParentFrame->StyleDisplay()->mDisplay == NS_STYLE_DISPLAY_INLINE)) ||
      // Things that are inline-outside but aren't inline frames are inline
      display->IsInlineOutsideStyle() ||
      // Popups that are certainly out of flow.
      isPopup;

    // Set mIsAllInline conservatively.  It just might be that even an inline
    // that has mIsAllInline false doesn't need an {ib} split.  So this is just
    // an optimization to keep from doing too much work in cases when we can
    // show that mIsAllInline is true..
    item->mIsAllInline = item->mHasInlineEnds = isInline ||
      // Figure out whether we're guaranteed this item will be out of flow.
      // This is not a precise test, since one of our ancestor inlines might add
      // an absolute containing block (if it's relatively positioned) when there
      // wasn't such a containing block before.  But it's conservative in the
      // sense that anything that will really end up as an in-flow non-inline
      // will test false here.  In other words, if this test is true we're
      // guaranteed to be inline; if it's false we don't know what we'll end up
      // as.
      //
      // If we make this test precise, we can remove some of the code dealing
      // with the imprecision in ConstructInline and adjust the comments on
      // mIsAllInline and mIsBlock in the header.  And probably remove mIsBlock
      // altogether, since then it will always be equal to !mHasInlineEnds.
      (!(bits & FCDATA_DISALLOW_OUT_OF_FLOW) &&
       aState.GetGeometricParent(display, nullptr));

    // Set mIsBlock conservatively.  It's OK to set it false for some real
    // blocks, but not OK to set it true for things that aren't blocks.  Since
    // isOutOfFlow might be false even in cases when the frame will end up
    // out-of-flow, we can't use it here.  But we _can_ say that the frame will
    // for sure end up in-flow if it's not floated or absolutely positioned.
    item->mIsBlock = !isInline &&
                     !display->IsAbsolutelyPositionedStyle() &&
                     !display->IsFloatingStyle() &&
                     !(bits & FCDATA_IS_SVG_TEXT);
  }

  if (item->mIsAllInline) {
    aItems.InlineItemAdded();
  } else if (item->mIsBlock) {
    aItems.BlockItemAdded();
  }

  // Our item should be treated as a line participant if we have the relevant
  // bit and are going to be in-flow.  Note that this really only matters if
  // our ancestor is a box or some such, so the fact that we might have an
  // inline ancestor that might become a containing block is not relevant here.
  if ((bits & FCDATA_IS_LINE_PARTICIPANT) &&
      ((bits & FCDATA_DISALLOW_OUT_OF_FLOW) ||
       !aState.GetGeometricParent(display, nullptr))) {
    item->mIsLineParticipant = true;
    aItems.LineParticipantItemAdded();
  }
}

static void
DestroyContent(void* aPropertyValue)
{
  nsIContent* content = static_cast<nsIContent*>(aPropertyValue);
  content->UnbindFromTree();
  NS_RELEASE(content);
}

NS_DECLARE_FRAME_PROPERTY(BeforeProperty, DestroyContent)
NS_DECLARE_FRAME_PROPERTY(AfterProperty, DestroyContent)

static const FramePropertyDescriptor*
GenConPseudoToProperty(nsIAtom* aPseudo)
{
  NS_ASSERTION(aPseudo == nsCSSPseudoElements::before ||
               aPseudo == nsCSSPseudoElements::after,
               "Bad gen-con pseudo");
  return aPseudo == nsCSSPseudoElements::before ? BeforeProperty()
      : AfterProperty();
}

/**
 * Return true if the frame construction item pointed to by aIter will
 * create a frame adjacent to a line boundary in the frame tree, and that
 * line boundary is induced by a content node adjacent to the frame's
 * content node in the content tree. The latter condition is necessary so
 * that ContentAppended/ContentInserted/ContentRemoved can easily find any
 * text nodes that were suppressed here.
 */
bool
nsCSSFrameConstructor::AtLineBoundary(FCItemIterator& aIter)
{
  if (aIter.item().mSuppressWhiteSpaceOptimizations) {
    return false;
  }

  if (aIter.AtStart()) {
    if (aIter.List()->HasLineBoundaryAtStart() &&
        !aIter.item().mContent->GetPreviousSibling())
      return true;
  } else {
    FCItemIterator prev = aIter;
    prev.Prev();
    if (prev.item().IsLineBoundary() &&
        !prev.item().mSuppressWhiteSpaceOptimizations &&
        aIter.item().mContent->GetPreviousSibling() == prev.item().mContent)
      return true;
  }

  FCItemIterator next = aIter;
  next.Next();
  if (next.IsDone()) {
    if (aIter.List()->HasLineBoundaryAtEnd() &&
        !aIter.item().mContent->GetNextSibling())
      return true;
  } else {
    if (next.item().IsLineBoundary() &&
        !next.item().mSuppressWhiteSpaceOptimizations &&
        aIter.item().mContent->GetNextSibling() == next.item().mContent)
      return true;
  }

  return false;
}

void
nsCSSFrameConstructor::ConstructFramesFromItem(nsFrameConstructorState& aState,
                                               FCItemIterator& aIter,
                                               nsIFrame* aParentFrame,
                                               nsFrameItems& aFrameItems)
{
  nsIFrame* adjParentFrame = aParentFrame;
  FrameConstructionItem& item = aIter.item();
  nsStyleContext* styleContext = item.mStyleContext;
  AdjustParentFrame(adjParentFrame, item.mFCData, styleContext);

  if (item.mIsText) {
    // If this is collapsible whitespace next to a line boundary,
    // don't create a frame. item.IsWhitespace() also sets the
    // NS_CREATE_FRAME_IF_NON_WHITESPACE flag in the text node. (If we
    // end up creating a frame, nsTextFrame::Init will clear the flag.)
    // We don't do this for generated content, because some generated
    // text content is empty text nodes that are about to be initialized.
    // (We check mAdditionalStateBits because only the generated content
    // container's frame construction item is marked with
    // mIsGeneratedContent, and we might not have an aParentFrame.)
    // We don't do it for content that may have XBL anonymous siblings,
    // because they make it difficult to correctly create the frame
    // due to dynamic changes.
    // We don't do it for SVG text, since we might need to position and
    // measure the white space glyphs due to x/y/dx/dy attributes.
    if (AtLineBoundary(aIter) &&
        !styleContext->StyleText()->WhiteSpaceOrNewlineIsSignificant() &&
        aIter.List()->ParentHasNoXBLChildren() &&
        !(aState.mAdditionalStateBits & NS_FRAME_GENERATED_CONTENT) &&
        (item.mFCData->mBits & FCDATA_IS_LINE_PARTICIPANT) &&
        !(item.mFCData->mBits & FCDATA_IS_SVG_TEXT) &&
        item.IsWhitespace(aState))
      return;

    ConstructTextFrame(item.mFCData, aState, item.mContent,
                       adjParentFrame, styleContext,
                       aFrameItems);
    return;
  }

  // Start background loads during frame construction so that we're
  // guaranteed that they will be started before onload fires.
  styleContext->StartBackgroundImageLoads();

  nsFrameState savedStateBits = aState.mAdditionalStateBits;
  if (item.mIsGeneratedContent) {
    // Ensure that frames created here are all tagged with
    // NS_FRAME_GENERATED_CONTENT.
    aState.mAdditionalStateBits |= NS_FRAME_GENERATED_CONTENT;

    // Note that we're not necessarily setting this property on the primary
    // frame for the content for which this is generated content.  We might be
    // setting it on a table pseudo-frame inserted under that instead.  That's
    // OK, though; we just need to do the property set so that the content will
    // get cleaned up when the frame is destroyed.
    aParentFrame->Properties().Set(GenConPseudoToProperty(styleContext->GetPseudo()),
                                   item.mContent);

    // Now that we've passed ownership of item.mContent to the frame, unset
    // our generated content flag so we don't release or unbind it ourselves.
    item.mIsGeneratedContent = false;
  }

  // XXXbz maybe just inline ConstructFrameFromItemInternal here or something?
  ConstructFrameFromItemInternal(item, aState, adjParentFrame, aFrameItems);

  aState.mAdditionalStateBits = savedStateBits;
}


inline bool
IsRootBoxFrame(nsIFrame *aFrame)
{
  return (aFrame->GetType() == nsGkAtoms::rootFrame);
}

nsresult
nsCSSFrameConstructor::ReconstructDocElementHierarchy()
{
  Element* rootElement = mDocument->GetRootElement();
  if (!rootElement) {
    /* nothing to do */
    return NS_OK;
  }
  return RecreateFramesForContent(rootElement, false);
}

nsIFrame*
nsCSSFrameConstructor::GetFrameFor(nsIContent* aContent)
{
  // Get the primary frame associated with the content
  nsIFrame* frame = aContent->GetPrimaryFrame();

  if (!frame)
    return nullptr;

  // If the content of the frame is not the desired content then this is not
  // really a frame for the desired content.
  // XXX This check is needed due to bug 135040. Remove it once that's fixed.
  if (frame->GetContent() != aContent) {
    return nullptr;
  }

  nsIFrame* insertionFrame = frame->GetContentInsertionFrame();

  NS_ASSERTION(insertionFrame == frame || !frame->IsLeaf(),
    "The insertion frame is the primary frame or the primary frame isn't a leaf");

  return insertionFrame;
}

nsIFrame*
nsCSSFrameConstructor::GetAbsoluteContainingBlock(nsIFrame* aFrame,
                                                  ContainingBlockType aType)
{
  NS_PRECONDITION(nullptr != mRootElementFrame, "no root element frame");

  // Starting with aFrame, look for a frame that is absolutely positioned or
  // relatively positioned (and transformed, if aType is FIXED)
  for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent()) {
    if (frame->IsFrameOfType(nsIFrame::eMathML)) {
      // If it's mathml, bail out -- no absolute positioning out from inside
      // mathml frames.  Note that we don't make this part of the loop
      // condition because of the stuff at the end of this method...
      return nullptr;
    }

    // If the frame is positioned, we will probably return it as the containing
    // block (see the exceptions below).  Otherwise, we'll start looking at the
    // parent frame, unless we're dealing with a scrollframe.
    // Scrollframes are special since they're not positioned, but their
    // scrolledframe might be.  So, we need to check this special case to return
    // the correct containing block (the scrolledframe) in that case.
    // If we're looking for a fixed-pos containing block and the frame is
    // not transformed, skip it.
    if (!frame->IsPositioned() ||
        (aType == FIXED_POS && !frame->StyleDisplay()->HasTransform(frame))) {
      continue;
    }
    nsIFrame* absPosCBCandidate = nullptr;
    if (frame->GetType() == nsGkAtoms::scrollFrame) {
      nsIScrollableFrame* scrollFrame = do_QueryFrame(frame);
      absPosCBCandidate = scrollFrame->GetScrolledFrame();
    } else {
      // Only first continuations can be containing blocks.
      absPosCBCandidate = frame->GetFirstContinuation();
    }
    // Is the frame really an absolute container?
    if (!absPosCBCandidate || !absPosCBCandidate->IsAbsoluteContainer()) {
      continue;
    }

    // For tables, skip the inner frame and consider the outer table frame.
    if (absPosCBCandidate->GetType() == nsGkAtoms::tableFrame) {
      continue;
    }
    // For outer table frames, we can just return absPosCBCandidate.
    return absPosCBCandidate;
  }

  // It is possible for the search for the containing block to fail, because
  // no absolute container can be found in the parent chain.  In those cases,
  // we fall back to the document element's containing block.
  if (aType == FIXED_POS) {
    return mFixedContainingBlock;
  }
  return mHasRootAbsPosContainingBlock ? mDocElementContainingBlock : nullptr;
}

nsIFrame*
nsCSSFrameConstructor::GetFloatContainingBlock(nsIFrame* aFrame)
{
  // Starting with aFrame, look for a frame that is a float containing block.
  // IF we hit a mathml frame, bail out; we don't allow floating out of mathml
  // frames, because they don't seem to be able to deal.
  // The logic here needs to match the logic in ProcessChildren()
  for (nsIFrame* containingBlock = aFrame;
       containingBlock &&
         !ShouldSuppressFloatingOfDescendants(containingBlock);
       containingBlock = containingBlock->GetParent()) {
    if (containingBlock->IsFloatContainingBlock()) {
      return containingBlock;
    }
  }

  // If we didn't find a containing block, then there just isn't
  // one.... return null
  return nullptr;
}

/**
 * This function will check whether aContainer has :after generated content.
 * If so, appending to it should actually insert.  The return value is the
 * parent to use for newly-appended content.  *aAfterFrame points to the :after
 * frame before which appended content should go, if there is one.
 */
static nsIFrame*
AdjustAppendParentForAfterContent(nsPresContext* aPresContext,
                                  nsIContent* aContainer,
                                  nsIFrame* aParentFrame,
                                  nsIFrame** aAfterFrame)
{
  // See if the parent has an :after pseudo-element.  Check for the presence
  // of style first, since nsLayoutUtils::GetAfterFrame is sorta expensive.
  nsStyleContext* parentStyle = aParentFrame->StyleContext();
  if (nsLayoutUtils::HasPseudoStyle(aContainer, parentStyle,
                                    nsCSSPseudoElements::ePseudo_after,
                                    aPresContext)) {
    // Ensure that the :after frame is on the principal child list.
    aParentFrame->DrainSelfOverflowList();

    nsIFrame* afterFrame = nsLayoutUtils::GetAfterFrame(aParentFrame);
    if (afterFrame) {
      *aAfterFrame = afterFrame;
      return afterFrame->GetParent();
    }
  }

  *aAfterFrame = nullptr;

  if (IsFrameSpecial(aParentFrame)) {
    // We might be in a situation where the last part of the {ib} split was
    // empty.  Since we have no ::after pseudo-element, we do in fact want to be
    // appending to that last part, so advance to it if needed.  Note that here
    // aParentFrame is the result of a GetLastSpecialSibling call, so must be
    // either the last or next to last special sibling.
    nsIFrame* trailingInline = GetSpecialSibling(aParentFrame);
    if (trailingInline) {
      aParentFrame = trailingInline;
    }

    // Always make sure to look at the last continuation of the frame
    // for the {ib} case, even if that continuation is empty.  We
    // don't do this for the non-special-frame case, since in the
    // other cases appending to the last nonempty continuation is fine
    // and in fact not doing that can confuse code that doesn't know
    // to pull kids from continuations other than its next one.
    aParentFrame = aParentFrame->GetLastContinuation();
  }

  return aParentFrame;
}

/**
 * This function will get the previous sibling to use for an append operation.
 * it takes a parent frame (must not be null) and its :after frame (may be
 * null).
 */
static nsIFrame*
FindAppendPrevSibling(nsIFrame* aParentFrame, nsIFrame* aAfterFrame)
{
  if (aAfterFrame) {
    NS_ASSERTION(aAfterFrame->GetParent() == aParentFrame, "Wrong parent");
    NS_ASSERTION(aAfterFrame->GetPrevSibling() ||
                 aParentFrame->GetFirstPrincipalChild() == aAfterFrame,
                 ":after frame must be on the principal child list here");
    return aAfterFrame->GetPrevSibling();
  }

  aParentFrame->DrainSelfOverflowList();

  return aParentFrame->GetLastChild(kPrincipalList);
}

/**
 * This function will get the next sibling for a frame insert operation given
 * the parent and previous sibling.  aPrevSibling may be null.
 */
static nsIFrame*
GetInsertNextSibling(nsIFrame* aParentFrame, nsIFrame* aPrevSibling)
{
  if (aPrevSibling) {
    return aPrevSibling->GetNextSibling();
  }

  return aParentFrame->GetFirstPrincipalChild();
}

/**
 * This function is called by ContentAppended() and ContentInserted() when
 * appending flowed frames to a parent's principal child list. It handles the
 * case where the parent is the trailing inline of an {ib} split.
 */
nsresult
nsCSSFrameConstructor::AppendFramesToParent(nsFrameConstructorState&       aState,
                                            nsIFrame*                      aParentFrame,
                                            nsFrameItems&                  aFrameList,
                                            nsIFrame*                      aPrevSibling,
                                            bool                           aIsRecursiveCall)
{
  NS_PRECONDITION(!IsFrameSpecial(aParentFrame) ||
                  !GetSpecialSibling(aParentFrame) ||
                  !GetSpecialSibling(aParentFrame)->GetFirstPrincipalChild(),
                  "aParentFrame has a special sibling with kids?");
  NS_PRECONDITION(!aPrevSibling || aPrevSibling->GetParent() == aParentFrame,
                  "Parent and prevsibling don't match");

  nsIFrame* nextSibling = ::GetInsertNextSibling(aParentFrame, aPrevSibling);

  NS_ASSERTION(nextSibling ||
               !aParentFrame->GetNextContinuation() ||
               !aParentFrame->GetNextContinuation()->GetFirstPrincipalChild() ||
               aIsRecursiveCall,
               "aParentFrame has later continuations with kids?");
  NS_ASSERTION(nextSibling ||
               !IsFrameSpecial(aParentFrame) ||
               (IsInlineFrame(aParentFrame) &&
                !GetSpecialSibling(aParentFrame) &&
                !aParentFrame->GetNextContinuation()) ||
               aIsRecursiveCall,
               "aParentFrame is not last?");

  // If we're inserting a list of frames at the end of the trailing inline
  // of an {ib} split, we may need to create additional {ib} siblings to parent
  // them.
  if (!nextSibling && IsFrameSpecial(aParentFrame)) {
    // When we get here, our frame list might start with a block.  If it does
    // so, and aParentFrame is an inline, and it and all its previous
    // continuations have no siblings, then put the initial blocks from the
    // frame list into the previous block of the {ib} split.  Note that we
    // didn't want to stop at the block part of the split when figuring out
    // initial parent, because that could screw up float parenting; it's easier
    // to do this little fixup here instead.
    if (aFrameList.NotEmpty() && !aFrameList.FirstChild()->IsInlineOutside()) {
      // See whether our trailing inline is empty
      nsIFrame* firstContinuation = aParentFrame->GetFirstContinuation();
      if (firstContinuation->PrincipalChildList().IsEmpty()) {
        // Our trailing inline is empty.  Collect our starting blocks from
        // aFrameList, get the right parent frame for them, and put them in.
        nsFrameList::FrameLinkEnumerator firstNonBlockEnumerator =
          FindFirstNonBlock(aFrameList);
        nsFrameList blockKids = aFrameList.ExtractHead(firstNonBlockEnumerator);
        NS_ASSERTION(blockKids.NotEmpty(), "No blocks?");

        nsIFrame* prevBlock =
          GetSpecialPrevSibling(firstContinuation)->GetLastContinuation();
        NS_ASSERTION(prevBlock, "Should have previous block here");

        MoveChildrenTo(aState.mPresContext, aParentFrame, prevBlock, blockKids);
      }
    }

    // We want to put some of the frames into this inline frame.
    nsFrameList::FrameLinkEnumerator firstBlockEnumerator(aFrameList);
    FindFirstBlock(firstBlockEnumerator);

    nsFrameList inlineKids = aFrameList.ExtractHead(firstBlockEnumerator);
    if (!inlineKids.IsEmpty()) {
      AppendFrames(aParentFrame, kPrincipalList, inlineKids);
    }

    if (!aFrameList.IsEmpty()) {
      const nsStyleDisplay* parentDisplay = aParentFrame->StyleDisplay();
      bool positioned =
        parentDisplay->mPosition == NS_STYLE_POSITION_RELATIVE &&
        !aParentFrame->IsSVGText();
      nsFrameItems ibSiblings;
      CreateIBSiblings(aState, aParentFrame, positioned, aFrameList,
                       ibSiblings);

      // Make sure to trigger reflow of the inline that used to be our
      // last one and now isn't anymore, since its GetSkipSides() has
      // changed.
      mPresShell->FrameNeedsReflow(aParentFrame,
                                   nsIPresShell::eTreeChange,
                                   NS_FRAME_HAS_DIRTY_CHILDREN);

      // Recurse so we create new ib siblings as needed for aParentFrame's parent
      return AppendFramesToParent(aState, aParentFrame->GetParent(), ibSiblings,
                                  aParentFrame, true);
    }

    return NS_OK;
  }
  
  // Insert the frames after our aPrevSibling
  return InsertFrames(aParentFrame, kPrincipalList, aPrevSibling, aFrameList);
}

#define UNSET_DISPLAY 255

// This gets called to see if the frames corresponding to aSibling and aContent
// should be siblings in the frame tree. Although (1) rows and cols, (2) row
// groups and col groups, (3) row groups and captions, (4) legends and content
// inside fieldsets, (5) popups and other kids of the menu are siblings from a
// content perspective, they are not considered siblings in the frame tree.
bool
nsCSSFrameConstructor::IsValidSibling(nsIFrame*              aSibling,
                                      nsIContent*            aContent,
                                      uint8_t&               aDisplay)
{
  nsIFrame* parentFrame = aSibling->GetParent();
  nsIAtom* parentType = nullptr;
  nsIAtom* grandparentType = nullptr;
  if (parentFrame) {
    parentType = parentFrame->GetType();
    nsIFrame* grandparentFrame = parentFrame->GetParent();
    if (grandparentFrame) {
      grandparentType = grandparentFrame->GetType();
    }
  }

  uint8_t siblingDisplay = aSibling->GetDisplay();
  if ((NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP == siblingDisplay) ||
      (NS_STYLE_DISPLAY_TABLE_COLUMN       == siblingDisplay) ||
      (NS_STYLE_DISPLAY_TABLE_CAPTION      == siblingDisplay) ||
      (NS_STYLE_DISPLAY_TABLE_HEADER_GROUP == siblingDisplay) ||
      (NS_STYLE_DISPLAY_TABLE_ROW_GROUP    == siblingDisplay) ||
      (NS_STYLE_DISPLAY_TABLE_FOOTER_GROUP == siblingDisplay) ||
      nsGkAtoms::menuFrame == parentType) {
    // if we haven't already, construct a style context to find the display type of aContent
    if (UNSET_DISPLAY == aDisplay) {
      nsRefPtr<nsStyleContext> styleContext;
      nsIFrame* styleParent = aSibling->GetParentStyleContextFrame();
      if (!styleParent) {
        NS_NOTREACHED("Shouldn't happen");
        return false;
      }
      // XXXbz when this code is killed, the state argument to
      // ResolveStyleContext can be made non-optional.
      styleContext = ResolveStyleContext(styleParent, aContent, nullptr);
      if (!styleContext) return false;
      const nsStyleDisplay* display = styleContext->StyleDisplay();
      aDisplay = display->mDisplay;
    }
    if (nsGkAtoms::menuFrame == parentType) {
      return
        (NS_STYLE_DISPLAY_POPUP == aDisplay) ==
        (NS_STYLE_DISPLAY_POPUP == siblingDisplay);
    }
    // To have decent performance we want to return false in cases in which
    // reordering the two siblings has no effect on display.  To ensure
    // correctness, we MUST return false in cases where the two siblings have
    // the same desired parent type and live on different display lists.
    // Specificaly, columns and column groups should only consider columns and
    // column groups as valid siblings.  Captions should only consider other
    // captions.  All other things should consider each other as valid
    // siblings.  The restriction in the |if| above on siblingDisplay is ok,
    // because for correctness the only part that really needs to happen is to
    // not consider captions, column groups, and row/header/footer groups
    // siblings of each other.  Treating a column or colgroup as a valid
    // sibling of a non-table-related frame will just mean we end up reframing.
    if ((siblingDisplay == NS_STYLE_DISPLAY_TABLE_CAPTION) !=
        (aDisplay == NS_STYLE_DISPLAY_TABLE_CAPTION)) {
      // One's a caption and the other is not.  Not valid siblings.
      return false;
    }

    if ((siblingDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP ||
         siblingDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN) !=
        (aDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN_GROUP ||
         aDisplay == NS_STYLE_DISPLAY_TABLE_COLUMN)) {
      // One's a column or column group and the other is not.  Not valid
      // siblings.
      return false;
    }

    return true;
  }
  else if (nsGkAtoms::fieldSetFrame == parentType ||
           (nsGkAtoms::fieldSetFrame == grandparentType &&
            nsGkAtoms::blockFrame == parentType)) {
    // Legends can be sibling of legends but not of other content in the fieldset
    nsIAtom* sibType = aSibling->GetContentInsertionFrame()->GetType();
    nsCOMPtr<nsIDOMHTMLLegendElement> legendContent(do_QueryInterface(aContent));

    if ((legendContent  && (nsGkAtoms::legendFrame != sibType)) ||
        (!legendContent && (nsGkAtoms::legendFrame == sibType)))
      return false;
  }

  return true;
}

nsIFrame*
nsCSSFrameConstructor::FindFrameForContentSibling(nsIContent* aContent,
                                                  nsIContent* aTargetContent,
                                                  uint8_t& aTargetContentDisplay,
                                                  bool aPrevSibling)
{
  nsIFrame* sibling = aContent->GetPrimaryFrame();
  if (!sibling || sibling->GetContent() != aContent) {
    // XXX the GetContent() != aContent check is needed due to bug 135040.
    // Remove it once that's fixed.
    return nullptr;
  }

  // If the frame is out-of-flow, GetPrimaryFrame() will have returned the
  // out-of-flow frame; we want the placeholder.
  if (sibling->GetStateBits() & NS_FRAME_OUT_OF_FLOW) {
    nsIFrame* placeholderFrame = GetPlaceholderFrameFor(sibling);
    NS_ASSERTION(placeholderFrame, "no placeholder for out-of-flow frame");
    sibling = placeholderFrame;
  }

  // The frame we have now should never be a continuation
  NS_ASSERTION(!sibling->GetPrevContinuation(), "How did that happen?");

  if (aPrevSibling) {
    // The frame may be a special frame (a split inline frame that
    // contains a block).  Get the last part of that split.
    if (IsFrameSpecial(sibling)) {
      sibling = GetLastSpecialSibling(sibling, true);
    }

    // The frame may have a continuation. If so, we want the last
    // non-overflow-container continuation as our previous sibling.
    sibling = sibling->GetTailContinuation();
  }

  if (aTargetContent &&
      !IsValidSibling(sibling, aTargetContent, aTargetContentDisplay)) {
    sibling = nullptr;
  }

  return sibling;
}

nsIFrame*
nsCSSFrameConstructor::FindPreviousSibling(FlattenedChildIterator aIter,
                                           uint8_t& aTargetContentDisplay)
{
  nsIContent* child = aIter.Get();

  // Note: not all content objects are associated with a frame (e.g., if it's
  // `display: none') so keep looking until we find a previous frame
  while (nsIContent* sibling = aIter.GetPreviousChild()) {
    nsIFrame* prevSibling =
      FindFrameForContentSibling(sibling, child, aTargetContentDisplay, true);

    if (prevSibling) {
      // Found a previous sibling, we're done!
      return prevSibling;
    }
  }

  return nullptr;
}

nsIFrame*
nsCSSFrameConstructor::FindNextSibling(FlattenedChildIterator aIter,
                                       uint8_t& aTargetContentDisplay)
{
  nsIContent* child = aIter.Get();

  while (nsIContent* sibling = aIter.GetNextChild()) {
    nsIFrame* nextSibling =
      FindFrameForContentSibling(sibling, child, aTargetContentDisplay, false);

    if (nextSibling) {
      // We found a next sibling, we're done!
      return nextSibling;
    }
  }

  return nullptr;
}

// For fieldsets, returns the area frame, if the child is not a legend. 
static nsIFrame*
GetAdjustedParentFrame(nsIFrame*       aParentFrame,
                       nsIAtom*        aParentFrameType,
                       nsIContent*     aChildContent)
{
  NS_PRECONDITION(nsGkAtoms::tableOuterFrame != aParentFrameType,
                  "Shouldn't be happening!");
  
  nsIFrame* newParent = nullptr;

  if (nsGkAtoms::fieldSetFrame == aParentFrameType) {
    // If the parent is a fieldSet, use the fieldSet's area frame as the
    // parent unless the new content is a legend. 
    nsCOMPtr<nsIDOMHTMLLegendElement> legendContent(do_QueryInterface(aChildContent));
    if (!legendContent) {
      newParent = GetFieldSetBlockFrame(aParentFrame);
    }
  }
  return (newParent) ? newParent : aParentFrame;
}

nsIFrame*
nsCSSFrameConstructor::GetInsertionPrevSibling(nsIFrame*& aParentFrame,
                                               nsIContent* aContainer,
                                               nsIContent* aChild,
                                               bool* aIsAppend,
                                               bool* aIsRangeInsertSafe,
                                               nsIContent* aStartSkipChild,
                                               nsIContent* aEndSkipChild)
{
  *aIsAppend = false;

  // Find the frame that precedes the insertion point. Walk backwards
  // from the parent frame to get the parent content, because if an
  // XBL insertion point is involved, we'll need to use _that_ to find
  // the preceding frame.

  NS_PRECONDITION(aParentFrame, "Must have parent frame to start with");
  nsIContent* container = aParentFrame->GetContent();

  FlattenedChildIterator iter(container);
  bool xblCase = iter.XBLInvolved() || container != aContainer;
  if (xblCase || !aChild->IsRootOfAnonymousSubtree()) {
    // The check for IsRootOfAnonymousSubtree() is because editor is
    // severely broken and calls us directly for native anonymous
    // nodes that it creates.
    if (aStartSkipChild) {
      iter.Seek(aStartSkipChild);
    } else {
      iter.Seek(aChild);
    }
  } else {
    // Prime the iterator for the call to FindPreviousSibling.
    iter.GetNextChild();
    NS_WARNING("Someone passed native anonymous content directly into frame "
               "construction.  Stop doing that!");
  }

  // Note that FindPreviousSibling is passed the iterator by value, so that
  // the later usage of the iterator starts from the same place.
  uint8_t childDisplay = UNSET_DISPLAY;
  nsIFrame* prevSibling = FindPreviousSibling(iter, childDisplay);

  // Now, find the geometric parent so that we can handle
  // continuations properly. Use the prev sibling if we have it;
  // otherwise use the next sibling.
  if (prevSibling) {
    aParentFrame = prevSibling->GetParent()->GetContentInsertionFrame();
  }
  else {
    // If there is no previous sibling, then find the frame that follows
    if (aEndSkipChild) {
      iter.Seek(aEndSkipChild);
      iter.GetPreviousChild();
    }
    nsIFrame* nextSibling = FindNextSibling(iter, childDisplay);

    if (nextSibling) {
      aParentFrame = nextSibling->GetParent()->GetContentInsertionFrame();
    }
    else {
      // No previous or next sibling, so treat this like an appended frame.
      *aIsAppend = true;
      if (IsFrameSpecial(aParentFrame)) {
        // Since we're appending, we'll walk to the last anonymous frame
        // that was created for the broken inline frame.  But don't walk
        // to the trailing inline if it's empty; stop at the block.
        aParentFrame = GetLastSpecialSibling(aParentFrame, false);
      }
      // Get continuation that parents the last child.  This MUST be done
      // before the AdjustAppendParentForAfterContent call.
      aParentFrame = nsLayoutUtils::GetLastContinuationWithChild(aParentFrame);
      // Deal with fieldsets
      aParentFrame = ::GetAdjustedParentFrame(aParentFrame,
                                              aParentFrame->GetType(),
                                              aChild);
      nsIFrame* appendAfterFrame;
      aParentFrame =
        ::AdjustAppendParentForAfterContent(mPresShell->GetPresContext(),
                                            container, aParentFrame,
                                            &appendAfterFrame);
      prevSibling = ::FindAppendPrevSibling(aParentFrame, appendAfterFrame);
    }
  }

  *aIsRangeInsertSafe = (childDisplay == UNSET_DISPLAY);
  return prevSibling;
}

static bool
IsSpecialFramesetChild(nsIContent* aContent)
{
  // IMPORTANT: This must match the conditions in nsHTMLFramesetFrame::Init.
  return aContent->IsHTML() &&
    (aContent->Tag() == nsGkAtoms::frameset ||
     aContent->Tag() == nsGkAtoms::frame);
}

static void
InvalidateCanvasIfNeeded(nsIPresShell* presShell, nsIContent* node);

#ifdef MOZ_XUL

static
bool
IsXULListBox(nsIContent* aContainer)
{
  return (aContainer->IsXUL() && aContainer->Tag() == nsGkAtoms::listbox);
}

static
nsListBoxBodyFrame*
MaybeGetListBoxBodyFrame(nsIContent* aContainer, nsIContent* aChild)
{
  if (!aContainer)
    return nullptr;

  if (IsXULListBox(aContainer) &&
      aChild->IsXUL() && aChild->Tag() == nsGkAtoms::listitem) {
    nsCOMPtr<nsIDOMXULElement> xulElement = do_QueryInterface(aContainer);
    nsCOMPtr<nsIBoxObject> boxObject;
    xulElement->GetBoxObject(getter_AddRefs(boxObject));
    nsCOMPtr<nsPIListBoxObject> listBoxObject = do_QueryInterface(boxObject);
    if (listBoxObject) {
      return listBoxObject->GetListBoxBody(false);
    }
  }

  return nullptr;
}
#endif

void
nsCSSFrameConstructor::AddTextItemIfNeeded(nsFrameConstructorState& aState,
                                           nsIFrame* aParentFrame,
                                           nsIContent* aPossibleTextContent,
                                           FrameConstructionItemList& aItems)
{
  NS_PRECONDITION(aPossibleTextContent, "Must have node");
  if (!aPossibleTextContent->IsNodeOfType(nsINode::eTEXT) ||
      !aPossibleTextContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE)) {
    // Not text, or not suppressed due to being all-whitespace (if it
    // were being suppressed, it would have the
    // NS_CREATE_FRAME_IF_NON_WHITESPACE flag)
    return;
  }
  NS_ASSERTION(!aPossibleTextContent->GetPrimaryFrame(),
               "Text node has a frame and NS_CREATE_FRAME_IF_NON_WHITESPACE");
  AddFrameConstructionItems(aState, aPossibleTextContent, false,
                            aParentFrame, aItems);
}

void
nsCSSFrameConstructor::ReframeTextIfNeeded(nsIContent* aParentContent,
                                           nsIContent* aContent)
{
  if (!aContent->IsNodeOfType(nsINode::eTEXT) ||
      !aContent->HasFlag(NS_CREATE_FRAME_IF_NON_WHITESPACE)) {
    // Not text, or not suppressed due to being all-whitespace (if it
    // were being suppressed, it would have the
    // NS_CREATE_FRAME_IF_NON_WHITESPACE flag)
    return;
  }
  NS_ASSERTION(!aContent->GetPrimaryFrame(),
               "Text node has a frame and NS_CREATE_FRAME_IF_NON_WHITESPACE");
  ContentInserted(aParentContent, aContent, nullptr, false);
}

// For inserts aChild should be valid, for appends it should be null.
// Returns true if this operation can be lazy, false if not.
bool
nsCSSFrameConstructor::MaybeConstructLazily(Operation aOperation,
                                            nsIContent* aContainer,
                                            nsIContent* aChild)
{
  if (mPresShell->GetPresContext()->IsChrome() || !aContainer ||
      aContainer->IsInNativeAnonymousSubtree() || aContainer->IsXUL()) {
    return false;
  }

  if (aOperation == CONTENTINSERT) {
    if (aChild->IsRootOfAnonymousSubtree() ||
        aChild->IsEditable() || aChild->IsXUL()) {
      return false;
    }
  } else { // CONTENTAPPEND
    NS_ASSERTION(aOperation == CONTENTAPPEND,
                 "operation should be either insert or append");
    for (nsIContent* child = aChild; child; child = child->GetNextSibling()) {
      NS_ASSERTION(!child->IsRootOfAnonymousSubtree(),
                   "Should be coming through the CONTENTAPPEND case");
      if (child->IsXUL() || child->IsEditable()) {
        return false;
      }
    }
  }

  // We can construct lazily; just need to set suitable bits in the content