layout/base/nsCSSFrameConstructor.cpp
author Ting-Yu Lin <tlin@mozilla.com>
Mon, 05 Nov 2018 19:11:12 +0000
changeset 444456 09df5390e2fb01be435bf72a8c8e1c1948e45f62
parent 444213 66df568f60f633bb8e361be0a256cb4490330bf8
child 445195 de799bed67609bea8c3af156f40c676dc384647f
child 445322 4d4ab7227b767020252035e70d78d11f070c7efb
permissions -rw-r--r--
Bug 916972 - Eliminate nsIFrame::GetSplittableType() completely. r=mats,dholbert Currently, GetSplittableType() is called only in nsCSSFrameConstructor::CreateContinuingFrame(). The splittable concrete frames should inherit from nsSplittableFrame, and must explicitly create continuing frame in CreateContinuingFrame(). Thus, no need to maintain GetSplittableType(). Differential Revision: https://phabricator.services.mozilla.com/D10798

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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/ComputedStyleInlines.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/ErrorResult.h"
#include "mozilla/dom/GeneratedImageContent.h"
#include "mozilla/dom/HTMLDetailsElement.h"
#include "mozilla/dom/HTMLSelectElement.h"
#include "mozilla/dom/HTMLSummaryElement.h"
#include "mozilla/EventStates.h"
#include "mozilla/Likely.h"
#include "mozilla/LinkedList.h"
#include "mozilla/MemoryReporting.h"
#include "mozilla/PresShell.h"
#include "mozilla/ServoBindings.h"
#include "mozilla/ServoStyleSetInlines.h"
#include "mozilla/StaticPrefs.h"
#include "nsAbsoluteContainingBlock.h"
#include "nsCSSPseudoElements.h"
#include "nsAtom.h"
#include "nsIFrameInlines.h"
#include "nsGkAtoms.h"
#include "nsPresContext.h"
#include "nsIDocument.h"
#include "nsIDocumentInlines.h"
#include "nsTableFrame.h"
#include "nsTableColFrame.h"
#include "nsTableRowFrame.h"
#include "nsTableCellFrame.h"
#include "nsHTMLParts.h"
#include "nsIPresShell.h"
#include "nsUnicharUtils.h"
#include "nsViewManager.h"
#include "nsStyleConsts.h"
#ifdef MOZ_XUL
#include "nsXULElement.h"
#include "mozilla/dom/BoxObject.h"
#endif // MOZ_XUL
#include "nsContainerFrame.h"
#include "nsNameSpaceManager.h"
#include "nsComboboxControlFrame.h"
#include "nsListControlFrame.h"
#include "nsPlaceholderFrame.h"
#include "nsTableRowGroupFrame.h"
#include "nsIFormControl.h"
#include "nsCSSAnonBoxes.h"
#include "nsTextFragment.h"
#include "nsIAnonymousContentCreator.h"
#include "nsBindingManager.h"
#include "nsXBLBinding.h"
#include "nsContentUtils.h"
#include "nsIScriptError.h"
#ifdef XP_MACOSX
#include "nsIDocShell.h"
#endif
#include "ChildIterator.h"
#include "nsError.h"
#include "nsLayoutUtils.h"
#include "nsAutoPtr.h"
#include "nsBoxFrame.h"
#include "nsBoxLayout.h"
#include "nsFlexContainerFrame.h"
#include "nsGridContainerFrame.h"
#include "RubyUtils.h"
#include "nsRubyFrame.h"
#include "nsRubyBaseFrame.h"
#include "nsRubyBaseContainerFrame.h"
#include "nsRubyTextFrame.h"
#include "nsRubyTextContainerFrame.h"
#include "nsImageFrame.h"
#include "nsIObjectLoadingContent.h"
#include "nsTArray.h"
#include "mozilla/dom/CharacterData.h"
#include "mozilla/dom/Element.h"
#include "mozilla/dom/ElementInlines.h"
#include "mozilla/dom/HTMLInputElement.h"
#include "nsAutoLayoutPhase.h"
#include "nsStyleStructInlines.h"
#include "nsPageContentFrame.h"
#include "mozilla/RestyleManager.h"
#include "StickyScrollContainer.h"
#include "nsFieldSetFrame.h"
#include "nsInlineFrame.h"
#include "nsBlockFrame.h"
#include "nsCanvasFrame.h"
#include "nsFirstLetterFrame.h"
#include "nsGfxScrollFrame.h"
#include "nsPageFrame.h"
#include "nsSimplePageSequenceFrame.h"
#include "nsTableWrapperFrame.h"
#include "nsIScrollableFrame.h"
#include "nsBackdropFrame.h"
#include "nsTransitionManager.h"
#include "DetailsFrame.h"
#include "nsStyleConsts.h"

#ifdef MOZ_XUL
#include "nsIPopupContainer.h"
#endif
#ifdef ACCESSIBILITY
#include "nsAccessibilityService.h"
#endif

#include "nsXBLService.h"

#undef NOISY_FIRST_LETTER

#include "nsMathMLParts.h"
#include "mozilla/dom/SVGTests.h"
#include "nsSVGUtils.h"

#include "nsRefreshDriver.h"
#include "nsTextNode.h"
#include "ActiveLayerTracker.h"
#include "nsIPresShellInlines.h"

using namespace mozilla;
using namespace mozilla::dom;

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

nsIFrame*
NS_NewHTMLCanvasFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewHTMLVideoFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsContainerFrame*
NS_NewSVGOuterSVGFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsContainerFrame*
NS_NewSVGOuterSVGAnonChildFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGInnerSVGFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGGeometryFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGGFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGGenericContainerFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsContainerFrame*
NS_NewSVGForeignObjectFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGAFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGSwitchFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGSymbolFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGTextFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGContainerFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGUseFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGViewFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
extern nsIFrame*
NS_NewSVGLinearGradientFrame(nsIPresShell *aPresShell, ComputedStyle* aStyle);
extern nsIFrame*
NS_NewSVGRadialGradientFrame(nsIPresShell *aPresShell, ComputedStyle* aStyle);
extern nsIFrame*
NS_NewSVGStopFrame(nsIPresShell *aPresShell, ComputedStyle* aStyle);
nsContainerFrame*
NS_NewSVGMarkerFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsContainerFrame*
NS_NewSVGMarkerAnonChildFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
extern nsIFrame*
NS_NewSVGImageFrame(nsIPresShell *aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGClipPathFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGFilterFrame(nsIPresShell *aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGPatternFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGMaskFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGFEContainerFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGFELeafFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGFEImageFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);
nsIFrame*
NS_NewSVGFEUnstyledLeafFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);

#include "mozilla/dom/NodeInfo.h"
#include "prenv.h"
#include "nsNodeInfoManager.h"
#include "nsContentCreatorFunctions.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 "nsPopupSetFrame.h"
#include "nsTreeColFrame.h"
#include "nsIBoxObject.h"
#include "nsXULLabelFrame.h"

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

nsContainerFrame*
NS_NewRootBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsContainerFrame*
NS_NewDocElementBoxFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewDeckFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewLeafBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewStackFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewProgressMeterFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewRangeFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewImageBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewTextBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewGroupBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewButtonBoxFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewSplitterFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewMenuPopupFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewPopupSetFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewMenuFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle, uint32_t aFlags);

nsIFrame*
NS_NewMenuBarFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewTreeBodyFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

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

// end grid

nsIFrame*
NS_NewTitleBarFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewResizerFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);


#endif

nsHTMLScrollFrame*
NS_NewHTMLScrollFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle, bool aIsRoot);

nsXULScrollFrame*
NS_NewXULScrollFrame(nsIPresShell* aPresShell, ComputedStyle* aStyle,
                     bool aIsRoot, bool aClipAllDescendants);

nsIFrame*
NS_NewSliderFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewScrollbarFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewScrollbarButtonFrame (nsIPresShell* aPresShell, ComputedStyle* aStyle);

nsIFrame*
NS_NewImageFrameForContentProperty(nsIPresShell*, ComputedStyle*);

nsIFrame*
NS_NewImageFrameForGeneratedContentIndex(nsIPresShell*, ComputedStyle*);


#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/grid item.
static inline bool
IsAnonymousFlexOrGridItem(const nsIFrame* aFrame)
{
  const nsAtom* pseudoType = aFrame->Style()->GetPseudo();
  return pseudoType == nsCSSAnonBoxes::anonymousFlexItem() ||
         pseudoType == nsCSSAnonBoxes::anonymousGridItem();
}

// Returns true if aFrame is a flex/grid container.
static inline bool
IsFlexOrGridContainer(const nsIFrame* aFrame)
{
  const LayoutFrameType t = aFrame->Type();
  return t == LayoutFrameType::FlexContainer ||
         t == LayoutFrameType::GridContainer;
}

// Returns true IFF the given nsIFrame is a nsFlexContainerFrame and
// represents a -webkit-{inline-}box or -moz-{inline-}box container.
static inline bool
IsFlexContainerForLegacyBox(const nsIFrame* aFrame)
{
  return aFrame->IsFlexContainerFrame() &&
         aFrame->HasAnyStateBits(NS_STATE_FLEX_IS_EMULATING_LEGACY_BOX);
}

#if DEBUG
static void
AssertAnonymousFlexOrGridItemParent(const nsIFrame* aChild,
                                    const nsIFrame* aParent)
{
  MOZ_ASSERT(IsAnonymousFlexOrGridItem(aChild),
             "expected an anonymous flex or grid item child frame");
  MOZ_ASSERT(aParent, "expected a parent frame");
  const nsAtom* pseudoType = aChild->Style()->GetPseudo();
  if (pseudoType == nsCSSAnonBoxes::anonymousFlexItem()) {
    MOZ_ASSERT(aParent->IsFlexContainerFrame(),
               "anonymous flex items should only exist as children "
               "of flex container frames");
  } else {
    MOZ_ASSERT(aParent->IsGridContainerFrame(),
               "anonymous grid items should only exist as children "
               "of grid container frames");
  }
}
#else
#define AssertAnonymousFlexOrGridItemParent(x, y) do { /* nothing */ } while(0)
#endif

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

#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 }

#define UNREACHABLE_FCDATA()                                  \
  { 0, { (FrameCreationFunc)nullptr }, nullptr, nullptr }
//----------------------------------------------------------------------

/**
 * 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 for display: contents elements.
 */
static inline bool
IsDisplayContents(const Element* aElement)
{
  return aElement->IsDisplayContents();
}

static inline bool
IsDisplayContents(const nsIContent* aContent)
{
  return aContent->IsElement() && IsDisplayContents(aContent->AsElement());
}

/**
 * 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) ||
         nsSVGUtils::IsInSVGTextSubtree(aFrame);
}

/**
 * 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->IsXULBoxFrame() ||
    ::IsFlexOrGridContainer(aFrame);
}

/**
 * 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,
              nsContainerFrame* aNewParentFrame,
              nsIFrame* aFrame,
              bool aForceStyleReparent)
{
  aFrame->SetParent(aNewParentFrame);
  // We reparent frames for two reasons: to put them inside ::first-line, and to
  // put them inside some wrapper anonymous boxes.
  if (aForceStyleReparent) {
    aRestyleManager->ReparentComputedStyleForFirstLine(aFrame);
  }
}

static void
ReparentFrames(nsCSSFrameConstructor* aFrameConstructor,
               nsContainerFrame* aNewParentFrame,
               const nsFrameList& aFrameList,
               bool aForceStyleReparent)
{
  RestyleManager* restyleManager = aFrameConstructor->RestyleManager();
  for (nsIFrame* f : aFrameList) {
    ReparentFrame(restyleManager, aNewParentFrame, f, aForceStyleReparent);
  }
}

//----------------------------------------------------------------------
//
// 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
IsFramePartOfIBSplit(nsIFrame* aFrame)
{
  bool result = (aFrame->GetStateBits() & NS_FRAME_PART_OF_IBSPLIT) != 0;
  MOZ_ASSERT(!result || static_cast<nsBlockFrame*>(do_QueryFrame(aFrame)) ||
                        static_cast<nsInlineFrame*>(do_QueryFrame(aFrame)),
             "only block/inline frames can have NS_FRAME_PART_OF_IBSPLIT");
  return result;
}

static nsContainerFrame* GetIBSplitSibling(nsIFrame* aFrame)
{
  MOZ_ASSERT(IsFramePartOfIBSplit(aFrame), "Shouldn't call this");

  // We only store the "ib-split sibling" annotation with the first
  // frame in the continuation chain. Walk back to find that frame now.
  return aFrame->FirstContinuation()->
           GetProperty(nsIFrame::IBSplitSibling());
}

static nsContainerFrame* GetIBSplitPrevSibling(nsIFrame* aFrame)
{
  MOZ_ASSERT(IsFramePartOfIBSplit(aFrame), "Shouldn't call this");

  // We only store the ib-split sibling annotation with the first
  // frame in the continuation chain. Walk back to find that frame now.
  return aFrame->FirstContinuation()->
           GetProperty(nsIFrame::IBSplitPrevSibling());
}

static nsContainerFrame*
GetLastIBSplitSibling(nsIFrame* aFrame)
{
  for (nsIFrame* frame = aFrame, *next; ; frame = next) {
    next = GetIBSplitSibling(frame);
    if (!next) {
      return static_cast<nsContainerFrame*>(frame);
    }
  }
  MOZ_ASSERT_UNREACHABLE("unreachable code");
  return nullptr;
}

static void
SetFrameIsIBSplit(nsContainerFrame* aFrame, nsContainerFrame* aIBSplitSibling)
{
  MOZ_ASSERT(aFrame, "bad args!");

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

  // Mark the frame as ib-split.
  aFrame->AddStateBits(NS_FRAME_PART_OF_IBSPLIT);

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

    // Store the ib-split sibling (if we were given one) with the
    // first frame in the flow.
    aFrame->SetProperty(nsIFrame::IBSplitSibling(), aIBSplitSibling);
    aIBSplitSibling->SetProperty(nsIFrame::IBSplitPrevSibling(), aFrame);
  }
}

static nsIFrame*
GetIBContainingBlockFor(nsIFrame* aFrame)
{
  MOZ_ASSERT(IsFramePartOfIBSplit(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-ib-split frames which have a pseudo on their
    // ComputedStyle -- they're not the frames we're looking for!  In
    // particular, they may be hiding a real parent that _is_ in an ib-split.
    if (!IsFramePartOfIBSplit(parentFrame) &&
        !parentFrame->Style()->GetPseudo())
      break;

    aFrame = parentFrame;
  } while (1);

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

  return parentFrame;
}

// This is a bit slow, but sometimes we need it.
static bool
ParentIsWrapperAnonBox(nsIFrame* aParent)
{
  nsIFrame* maybeAnonBox = aParent;
  if (maybeAnonBox->Style()->GetPseudo() ==
        nsCSSAnonBoxes::cellContent()) {
    // The thing that would maybe be a wrapper anon box is the cell.
    maybeAnonBox = maybeAnonBox->GetParent();
  }
  return maybeAnonBox->Style()->IsWrapperAnonBox();
}

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

// 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).

inline void
SetInitialSingleChild(nsContainerFrame* aParent, nsIFrame* aFrame)
{
  MOZ_ASSERT(!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)
{
  MOZ_ASSERT(aChild, "nsFrameItems::AddChild");
  MOZ_ASSERT(!aChild->HasAnyStateBits(NS_FRAME_OUT_OF_FLOW) ||
             aChild->GetPlaceholderFrame(),
             "An out-of-flow child without a placeholder frame?");

  // 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
  nsContainerFrame* containingBlock;

  explicit nsAbsoluteItems(nsContainerFrame* 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
};

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

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

// 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

  RefPtr<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;
  // The containing block of a frame in the top layer is defined by the
  // spec: fixed-positioned frames are children of the viewport frame,
  // and absolutely-positioned frames are children of the initial
  // containing block. They would not be caught by any other containing
  // block, e.g. frames with transform or filter.
  nsAbsoluteItems           mTopLayerFixedItems;
  nsAbsoluteItems           mTopLayerAbsoluteItems;

  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 transform and filter properties, we want to hook
  // the abs-pos and fixed-pos lists together, since such
  // 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;

  // Constructor
  // Use the passed-in history state.
  nsFrameConstructorState(
    nsIPresShell* aPresShell,
    nsContainerFrame* aFixedContainingBlock,
    nsContainerFrame* aAbsoluteContainingBlock,
    nsContainerFrame* aFloatContainingBlock,
    already_AddRefed<nsILayoutHistoryState> aHistoryState);
  // Get the history state from the pres context's pres shell.
  nsFrameConstructorState(nsIPresShell* aPresShell,
                          nsContainerFrame* aFixedContainingBlock,
                          nsContainerFrame* aAbsoluteContainingBlock,
                          nsContainerFrame* 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(nsContainerFrame* 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(nsContainerFrame* 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.
  nsContainerFrame* GetGeometricParent(const nsStyleDisplay& aStyleDisplay,
                                       nsContainerFrame* 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 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,
                nsContainerFrame* 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(UniquePtr<PendingBinding> aPendingBinding)
  {
    if (mCurrentPendingBindingInsertionPoint) {
      mCurrentPendingBindingInsertionPoint->setPrevious(aPendingBinding.release());
    } else {
      mPendingBindings.insertBack(aPendingBinding.release());
    }
  }

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);

  /**
   * GetOutOfFlowFrameItems selects the out-of-flow frame list the new
   * frame should be added to. If the frame shouldn't be added to any
   * out-of-flow list, it returns nullptr. The corresponding type of
   * placeholder is also returned via the aPlaceholderType parameter
   * if this method doesn't return nullptr. The caller should check
   * whether the returned list really has a containing block.
   */
  nsAbsoluteItems* GetOutOfFlowFrameItems(nsIFrame* aNewFrame,
                                          bool aCanBePositioned,
                                          bool aCanBeFloated,
                                          bool aIsOutOfFlowPopup,
                                          nsFrameState* aPlaceholderType);

  void ConstructBackdropFrameFor(nsIContent* aContent, nsIFrame* aFrame);

  // 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,
  nsContainerFrame* aFixedContainingBlock,
  nsContainerFrame* aAbsoluteContainingBlock,
  nsContainerFrame* aFloatContainingBlock,
  already_AddRefed<nsILayoutHistoryState> aHistoryState)
  : mPresContext(aPresShell->GetPresContext()),
    mPresShell(aPresShell),
    mFrameManager(aPresShell->FrameConstructor()),
#ifdef MOZ_XUL
    mPopupItems(nullptr),
#endif
    mFixedItems(aFixedContainingBlock),
    mAbsoluteItems(aAbsoluteContainingBlock),
    mFloatedItems(aFloatContainingBlock),
    mTopLayerFixedItems(
      static_cast<nsContainerFrame*>(mFrameManager->GetRootFrame())),
    mTopLayerAbsoluteItems(
      aPresShell->FrameConstructor()->GetDocElementContainingBlock()),
    // See PushAbsoluteContaningBlock below
    mFrameState(aHistoryState),
    mAdditionalStateBits(nsFrameState(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),
    mCurrentPendingBindingInsertionPoint(nullptr)
{
#ifdef MOZ_XUL
  nsIPopupContainer* popupContainer =
    nsIPopupContainer::GetPopupContainer(aPresShell);
  if (popupContainer) {
    mPopupItems.containingBlock = popupContainer->GetPopupSetFrame();
  }
#endif
  MOZ_COUNT_CTOR(nsFrameConstructorState);
}

nsFrameConstructorState::nsFrameConstructorState(nsIPresShell* aPresShell,
                                                 nsContainerFrame* aFixedContainingBlock,
                                                 nsContainerFrame* aAbsoluteContainingBlock,
                                                 nsContainerFrame* aFloatContainingBlock)
  : nsFrameConstructorState(aPresShell,
                            aFixedContainingBlock,
                            aAbsoluteContainingBlock,
                            aFloatContainingBlock,
                            aPresShell->GetDocument()->GetLayoutHistoryState())
{
}

nsFrameConstructorState::~nsFrameConstructorState()
{
  MOZ_COUNT_DTOR(nsFrameConstructorState);
  ProcessFrameInsertions(mTopLayerFixedItems, nsIFrame::kFixedList);
  ProcessFrameInsertions(mTopLayerAbsoluteItems, nsIFrame::kAbsoluteList);
  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 nsContainerFrame*
AdjustAbsoluteContainingBlock(nsContainerFrame* aContainingBlockIn)
{
  if (!aContainingBlockIn) {
    return nullptr;
  }

  // Always use the container's first continuation. (Inline frames can have
  // non-fluid bidi continuations...)
  return static_cast<nsContainerFrame*>(aContainingBlockIn->FirstContinuation());
}

void
nsFrameConstructorState::PushAbsoluteContainingBlock(nsContainerFrame* 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->IsFixedPosContainingBlock();

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

void
nsFrameConstructorState::PushFloatContainingBlock(nsContainerFrame* aNewFloatContainingBlock,
                                                  nsFrameConstructorSaveState& aSaveState)
{
  MOZ_ASSERT(!aNewFloatContainingBlock ||
             aNewFloatContainingBlock->IsFloatContainingBlock(),
             "Please push a real float containing block!");
  NS_ASSERTION(!aNewFloatContainingBlock ||
               !ShouldSuppressFloatingOfDescendants(aNewFloatContainingBlock),
               "We should not push a frame that is supposed to _suppress_ "
               "floats as a float containing block!");
  aSaveState.mItems = &mFloatedItems;
  aSaveState.mSavedItems = mFloatedItems;
  aSaveState.mChildListID = nsIFrame::kFloatList;
  aSaveState.mState = this;
  mFloatedItems = nsAbsoluteItems(aNewFloatContainingBlock);
}

nsContainerFrame*
nsFrameConstructorState::GetGeometricParent(const nsStyleDisplay& aStyleDisplay,
                                            nsContainerFrame* aContentParentFrame) const
{
  // 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 table wrappers 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 &&
      nsSVGUtils::IsInSVGTextSubtree(aContentParentFrame)) {
    return aContentParentFrame;
  }

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

  if (aStyleDisplay.mTopLayer != NS_STYLE_TOP_LAYER_NONE) {
    MOZ_ASSERT(aStyleDisplay.mTopLayer == NS_STYLE_TOP_LAYER_TOP,
               "-moz-top-layer should be either none or top");
    MOZ_ASSERT(aStyleDisplay.IsAbsolutelyPositionedStyle(),
               "Top layer items should always be absolutely positioned");
    if (aStyleDisplay.mPosition == NS_STYLE_POSITION_FIXED) {
      MOZ_ASSERT(mTopLayerFixedItems.containingBlock, "No root frame?");
      return mTopLayerFixedItems.containingBlock;
    }
    MOZ_ASSERT(aStyleDisplay.mPosition == NS_STYLE_POSITION_ABSOLUTE);
    MOZ_ASSERT(mTopLayerAbsoluteItems.containingBlock);
    return mTopLayerAbsoluteItems.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;
}

nsAbsoluteItems*
nsFrameConstructorState::GetOutOfFlowFrameItems(nsIFrame* aNewFrame,
                                                bool aCanBePositioned,
                                                bool aCanBeFloated,
                                                bool aIsOutOfFlowPopup,
                                                nsFrameState* aPlaceholderType)
{
#ifdef MOZ_XUL
  if (MOZ_UNLIKELY(aIsOutOfFlowPopup)) {
    MOZ_ASSERT(mPopupItems.containingBlock, "Must have a popup set frame!");
    *aPlaceholderType = PLACEHOLDER_FOR_POPUP;
    return &mPopupItems;
  }
#endif // MOZ_XUL
  if (aCanBeFloated && aNewFrame->IsFloating()) {
    *aPlaceholderType = PLACEHOLDER_FOR_FLOAT;
    return &mFloatedItems;
  }

  if (aCanBePositioned) {
    const nsStyleDisplay* disp = aNewFrame->StyleDisplay();
    if (disp->mTopLayer != NS_STYLE_TOP_LAYER_NONE) {
      *aPlaceholderType = PLACEHOLDER_FOR_TOPLAYER;
      if (disp->mPosition == NS_STYLE_POSITION_FIXED) {
        *aPlaceholderType |= PLACEHOLDER_FOR_FIXEDPOS;
        return &mTopLayerFixedItems;
      }
      *aPlaceholderType |= PLACEHOLDER_FOR_ABSPOS;
      return &mTopLayerAbsoluteItems;
    }
    if (disp->mPosition == NS_STYLE_POSITION_ABSOLUTE) {
      *aPlaceholderType = PLACEHOLDER_FOR_ABSPOS;
      return &mAbsoluteItems;
    }
    if (disp->mPosition == NS_STYLE_POSITION_FIXED) {
      *aPlaceholderType = PLACEHOLDER_FOR_FIXEDPOS;
      return &GetFixedItems();
    }
  }
  return nullptr;
}

void
nsFrameConstructorState::ConstructBackdropFrameFor(nsIContent* aContent,
                                                   nsIFrame* aFrame)
{
  MOZ_ASSERT(aFrame->StyleDisplay()->mTopLayer == NS_STYLE_TOP_LAYER_TOP);
  nsContainerFrame* frame = do_QueryFrame(aFrame);
  if (!frame) {
    NS_WARNING("Cannot create backdrop frame for non-container frame");
    return;
  }

  RefPtr<ComputedStyle> style = mPresShell->StyleSet()->
    ResolvePseudoElementStyle(aContent->AsElement(),
                              CSSPseudoElementType::backdrop,
                              /* aParentComputedStyle */ nullptr,
                              /* aPseudoElement */ nullptr);
  MOZ_ASSERT(style->StyleDisplay()->mTopLayer == NS_STYLE_TOP_LAYER_TOP);
  nsContainerFrame* parentFrame =
    GetGeometricParent(*style->StyleDisplay(), nullptr);

  nsBackdropFrame* backdropFrame = new (mPresShell) nsBackdropFrame(style);
  backdropFrame->Init(aContent, parentFrame, nullptr);

  nsFrameState placeholderType;
  nsAbsoluteItems* frameItems = GetOutOfFlowFrameItems(backdropFrame,
                                                       true, true, false,
                                                       &placeholderType);
  MOZ_ASSERT(placeholderType & PLACEHOLDER_FOR_TOPLAYER);

  nsIFrame* placeholder = nsCSSFrameConstructor::
    CreatePlaceholderFrameFor(mPresShell, aContent, backdropFrame,
                              frame, nullptr, placeholderType);
  nsFrameList temp(placeholder, placeholder);
  frame->SetInitialChildList(nsIFrame::kBackdropList, temp);

  frameItems->AddChild(backdropFrame);
}

void
nsFrameConstructorState::AddChild(nsIFrame* aNewFrame,
                                  nsFrameItems& aFrameItems,
                                  nsIContent* aContent,
                                  nsContainerFrame* aParentFrame,
                                  bool aCanBePositioned,
                                  bool aCanBeFloated,
                                  bool aIsOutOfFlowPopup,
                                  bool aInsertAfter,
                                  nsIFrame* aInsertAfterFrame)
{
  MOZ_ASSERT(!aNewFrame->GetNextSibling(), "Shouldn't happen");

  nsFrameState placeholderType;
  nsAbsoluteItems* outOfFlowFrameItems =
    GetOutOfFlowFrameItems(aNewFrame, aCanBePositioned, aCanBeFloated,
                           aIsOutOfFlowPopup, &placeholderType);

  // The comments in GetGeometricParent regarding root table frames
  // all apply here, unfortunately. Thus, we need to check whether
  // the returned frame items really has containing block.
  nsFrameItems* frameItems;
  if (outOfFlowFrameItems && outOfFlowFrameItems->containingBlock) {
    MOZ_ASSERT(aNewFrame->GetParent() == outOfFlowFrameItems->containingBlock,
               "Parent of the frame is not the containing block?");
    frameItems = outOfFlowFrameItems;
  } else {
    frameItems = &aFrameItems;
    placeholderType = nsFrameState(0);
  }

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

    placeholderFrame->AddStateBits(mAdditionalStateBits);
    // Add the placeholder frame to the flow
    aFrameItems.AddChild(placeholderFrame);

    if (placeholderType & PLACEHOLDER_FOR_TOPLAYER) {
      ConstructBackdropFrameFor(aContent, aNewFrame);
    }
  }
#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 ||          \
                              &aFrameItems == &mTopLayerAbsoluteItems) && \
                             aChildListID == nsIFrame::kAbsoluteList) ||  \
                            ((&aFrameItems == &mFixedItems ||             \
                              &aFrameItems == &mTopLayerFixedItems) &&    \
                             aChildListID == nsIFrame::kFixedList)
#ifdef MOZ_XUL
  MOZ_ASSERT(NS_NONXUL_LIST_TEST ||
             (&aFrameItems == &mPopupItems &&
              aChildListID == nsIFrame::kPopupList),
             "Unexpected aFrameItems/aChildListID combination");
#else
  MOZ_ASSERT(NS_NONXUL_LIST_TEST,
             "Unexpected aFrameItems/aChildListID combination");
#endif

  if (aFrameItems.IsEmpty()) {
    return;
  }

  nsContainerFrame* 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);
  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()) {
      containingBlock->GetAbsoluteContainingBlock()->
        SetInitialChildList(containingBlock, aChildListID, aFrameItems);
    } else {
      containingBlock->SetInitialChildList(aChildListID, aFrameItems);
    }
  } else if (aChildListID == nsIFrame::kFixedList ||
             aChildListID == nsIFrame::kAbsoluteList) {
    // The order is not important for abs-pos/fixed-pos frame list, just
    // append the frame items to the list directly.
    mFrameManager->AppendFrames(containingBlock, 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();

    // Cache the ancestor chain so that we can reuse it if needed.
    AutoTArray<nsIFrame*, 20> firstNewFrameAncestors;
    nsIFrame* notCommonAncestor = nullptr;
    if (lastChild) {
      notCommonAncestor = nsLayoutUtils::FillAncestors(firstNewFrame,
                                                       containingBlock,
                                                       &firstNewFrameAncestors);
    }

    if (!lastChild ||
        nsLayoutUtils::CompareTreePosition(lastChild, firstNewFrame,
                                           firstNewFrameAncestors,
                                           notCommonAncestor ?
                                             containingBlock : nullptr) < 0) {
      // no lastChild, or lastChild comes before the new children, so just append
      mFrameManager->AppendFrames(containingBlock, aChildListID, aFrameItems);
    } else {
      // Try the other children. First collect them to an array so that a
      // reasonable fast binary search can be used to find the insertion point.
      AutoTArray<nsIFrame*, 128> children;
      for (nsIFrame* f = childList.FirstChild(); f != lastChild;
           f = f->GetNextSibling()) {
        children.AppendElement(f);
      }

      nsIFrame* insertionPoint = nullptr;
      int32_t imin = 0;
      int32_t max = children.Length();
      while (max > imin) {
        int32_t imid = imin + ((max - imin) / 2);
        nsIFrame* f = children[imid];
        int32_t compare =
          nsLayoutUtils::CompareTreePosition(f, firstNewFrame, firstNewFrameAncestors,
                                             notCommonAncestor ? containingBlock : nullptr);
        if (compare > 0) {
          // f is after the new frame.
          max = imid;
          insertionPoint = imid > 0 ? children[imid - 1] : nullptr;
        } else if (compare < 0) {
          // f is before the new frame.
          imin = imid + 1;
          insertionPoint = f;
        } else {
          // This is for the old behavior. Should be removed once it is
          // guaranteed that CompareTreePosition can't return 0!
          // See bug 928645.
          NS_WARNING("Something odd happening???");
          insertionPoint = nullptr;
          for (uint32_t i = 0; i < children.Length(); ++i) {
            nsIFrame* f = children[i];
            if (nsLayoutUtils::CompareTreePosition(f, firstNewFrame,
                                                   firstNewFrameAncestors,
                                                   notCommonAncestor ?
                                                     containingBlock : nullptr) > 0) {
              break;
            }
            insertionPoint = f;
          }
          break;
        }
      }
      mFrameManager->InsertFrames(containingBlock, aChildListID,
                                  insertionPoint, aFrameItems);
    }
  }

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


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");
  }
}

/**
 * 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.
 */
// 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(nsIFrame* aOldParent,
               nsContainerFrame* aNewParent,
               nsFrameList& aFrameList)
{
  bool sameGrandParent = aOldParent->GetParent() == aNewParent->GetParent();

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

static bool
ShouldCreateImageFrameForContent(const Element& aElement, ComputedStyle& aStyle)
{
  if (aElement.IsRootOfNativeAnonymousSubtree()) {
    return false;
  }

  auto& content = *aStyle.StyleContent();
  if (content.ContentCount() != 1) {
    return false;
  }

  return content.ContentAt(0).GetType() == StyleContentType::Image;
}

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

nsCSSFrameConstructor::nsCSSFrameConstructor(nsIDocument* aDocument,
                                             nsIPresShell* aPresShell)
  : nsFrameManager(aPresShell)
  , mDocument(aDocument)
  , mRootElementFrame(nullptr)
  , mRootElementStyleFrame(nullptr)
  , mDocElementContainingBlock(nullptr)
  , mPageSequenceFrame(nullptr)
  , mFirstFreeFCItem(nullptr)
  , mFCItemsInUse(0)
  , mCurrentDepth(0)
  , mQuotesDirty(false)
  , mCountersDirty(false)
  , mIsDestroyingFrameTree(false)
  , mHasRootAbsPosContainingBlock(false)
  , mAlwaysCreateFramesForIgnorableWhitespace(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)
{
  if (aFrame->GetStateBits() & NS_FRAME_GENERATED_CONTENT) {
    if (mQuoteList.DestroyNodesFor(aFrame))
      QuotesDirty();
  }

  if (aFrame->HasAnyStateBits(NS_FRAME_HAS_CSS_COUNTER_STYLE) &&
      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);
}

struct nsGenConInitializer {
  nsAutoPtr<nsGenConNode> mNode;
  nsGenConList*           mList;
  void (nsCSSFrameConstructor::*mDirtyAll)();

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

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

already_AddRefed<nsIContent>
nsCSSFrameConstructor::CreateGeneratedContent(nsFrameConstructorState& aState,
                                              const Element& aOriginatingElement,
                                              ComputedStyle& aPseudoStyle,
                                              uint32_t aContentIndex)
{
  // Get the content value
  const nsStyleContentData& data =
    aPseudoStyle.StyleContent()->ContentAt(aContentIndex);
  const StyleContentType type = data.GetType();

  switch (type) {
    case StyleContentType::Image:
      return GeneratedImageContent::Create(*mDocument, aContentIndex);

    case StyleContentType::String:
      return CreateGenConTextNode(aState,
                                  nsDependentString(data.GetString()),
                                  nullptr, nullptr);

    case StyleContentType::Attr: {
      const nsStyleContentAttr* attr = data.GetAttr();
      RefPtr<nsAtom> attrName = attr->mName;
      int32_t attrNameSpace = kNameSpaceID_None;
      if (RefPtr<nsAtom> ns = attr->mNamespaceURL) {
        nsresult rv =
          nsContentUtils::NameSpaceManager()->RegisterNameSpace(ns.forget(), attrNameSpace);
        NS_ENSURE_SUCCESS(rv, nullptr);
      }

      if (mDocument->IsHTMLDocument() && aOriginatingElement.IsHTMLElement()) {
        ToLowerCaseASCII(attrName);
      }

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

    case StyleContentType::Counter:
    case StyleContentType::Counters: {
      nsStyleContentData::CounterFunction* counters = data.GetCounters();
      nsCounterList* counterList =
        mCounterManager.CounterListFor(counters->mIdent);

      nsCounterUseNode* node =
        new nsCounterUseNode(counters, aContentIndex,
                             type == StyleContentType::Counters);

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

    case StyleContentType::OpenQuote:
    case StyleContentType::CloseQuote:
    case StyleContentType::NoOpenQuote:
    case StyleContentType::NoCloseQuote: {
      nsQuoteNode* node =
        new nsQuoteNode(type, aContentIndex);

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

    case StyleContentType::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 (aOriginatingElement.HasAttr(kNameSpaceID_None, nsGkAtoms::alt)) {
        nsCOMPtr<nsIContent> content;
        NS_NewAttributeContent(mDocument->NodeInfoManager(),
                               kNameSpaceID_None,
                               nsGkAtoms::alt,
                               getter_AddRefs(content));
        return content.forget();
      }

      if (aOriginatingElement.IsHTMLElement(nsGkAtoms::input)) {
        if (aOriginatingElement.HasAttr(kNameSpaceID_None, nsGkAtoms::value)) {
          nsCOMPtr<nsIContent> content;
          NS_NewAttributeContent(mDocument->NodeInfoManager(),
                                 kNameSpaceID_None, nsGkAtoms::value, getter_AddRefs(content));
          return content.forget();
        }

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

      break;
    }

    case StyleContentType::Uninitialized:
      MOZ_ASSERT_UNREACHABLE("uninitialized content type");
      return nullptr;
  }

  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,
                                                  nsContainerFrame* aParentFrame,
                                                  Element& aOriginatingElement,
                                                  ComputedStyle& aStyle,
                                                  CSSPseudoElementType aPseudoElement,
                                                  FrameConstructionItemList& aItems)
{
  MOZ_ASSERT(aPseudoElement == CSSPseudoElementType::before ||
             aPseudoElement == CSSPseudoElementType::after,
             "unexpected aPseudoElement");

  if (aParentFrame &&
      (aParentFrame->IsHTMLVideoFrame() || aParentFrame->IsDateTimeControlFrame())) {
    // Video frames and date time control frames may not be leafs when backed by an UA widget,
    // but we still don't want to expose generated content.
    MOZ_ASSERT(aOriginatingElement.GetShadowRoot()->IsUAWidget());
    return;
  }

  ServoStyleSet* styleSet = mPresShell->StyleSet();

  // Probe for the existence of the pseudo-element
  RefPtr<ComputedStyle> pseudoStyle =
    styleSet->ProbePseudoElementStyle(aOriginatingElement, aPseudoElement, &aStyle);
  if (!pseudoStyle) {
    return;
  }

  bool isBefore = aPseudoElement == CSSPseudoElementType::before;

  // |ProbePseudoStyleFor| checked the 'display' property and the
  // |ContentCount()| of the 'content' property for us.
  nsAtom* elemName = isBefore ?
    nsGkAtoms::mozgeneratedcontentbefore : nsGkAtoms::mozgeneratedcontentafter;
  RefPtr<NodeInfo> nodeInfo =
    mDocument->NodeInfoManager()->GetNodeInfo(elemName,
                                              nullptr,
                                              kNameSpaceID_None,
                                              nsINode::ELEMENT_NODE);
  RefPtr<Element> container;
  nsresult rv = NS_NewXMLElement(getter_AddRefs(container), nodeInfo.forget());
  if (NS_FAILED(rv)) {
    return;
  }

  // Cleared when the pseudo is unbound from the tree, so no need to store a
  // strong reference, nor a destructor.
  nsAtom* property = isBefore
    ? nsGkAtoms::beforePseudoProperty : nsGkAtoms::afterPseudoProperty;
  aOriginatingElement.SetProperty(property, container.get());

  container->SetIsNativeAnonymousRoot();
  container->SetPseudoElementType(aPseudoElement);

  // If the parent is in a shadow tree, make sure we don't
  // bind with a document because shadow roots and its descendants
  // are not in document.
  nsIDocument* bindDocument =
    aOriginatingElement.HasFlag(NODE_IS_IN_SHADOW_TREE) ? nullptr : mDocument;
  rv = container->BindToTree(bindDocument,
                             &aOriginatingElement,
                             &aOriginatingElement);
  if (NS_FAILED(rv)) {
    container->UnbindFromTree();
    return;
  }

  // Servo has already eagerly computed the style for the container, so we can
  // just stick the style on the element and avoid an additional traversal.
  //
  // We don't do this for pseudos that may trigger animations or transitions,
  // since those need to be kicked off by the traversal machinery.
  if (!Servo_ComputedValues_SpecifiesAnimationsOrTransitions(pseudoStyle)) {
    Servo_SetExplicitStyle(container, pseudoStyle);
  } else {
    // If animations are involved, we avoid the SetExplicitStyle optimization
    // above. We need to grab style with animations from the pseudo element and
    // replace old one.
    mPresShell->StyleSet()->StyleNewSubtree(container);
    pseudoStyle = styleSet->ResolveServoStyle(*container);
  }

  uint32_t contentCount = pseudoStyle->StyleContent()->ContentCount();
  for (uint32_t contentIndex = 0; contentIndex < contentCount; contentIndex++) {
    nsCOMPtr<nsIContent> content =
      CreateGeneratedContent(aState, aOriginatingElement, *pseudoStyle, contentIndex);
    if (!content) {
      continue;
    }
    // We don't strictly have to set NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE
    // here; it would get set under AppendChildTo.  But AppendChildTo might
    // think that we're going from not being anonymous to being anonymous and
    // do some extra work; setting the flag here avoids that.
    content->SetFlags(NODE_IS_IN_NATIVE_ANONYMOUS_SUBTREE);
    container->AppendChildTo(content, false);
    if (auto* element = Element::FromNode(content)) {
      // If we created any children elements, Servo needs to traverse them, but
      // the root is already set up.
      mPresShell->StyleSet()->StyleNewSubtree(element);
    }
  }

  AddFrameConstructionItemsInternal(aState,
                                    container,
                                    aParentFrame,
                                    true,
                                    pseudoStyle,
                                    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 a table wrapper 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 wrapper was a pseudo-frame.
static bool
IsTablePseudo(nsIFrame* aFrame)
{
  nsAtom* pseudoType = aFrame->Style()->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()->Style()->GetPseudo() ==
        nsCSSAnonBoxes::tableCell()) ||
     (pseudoType == nsCSSAnonBoxes::tableWrapper() &&
      (aFrame->PrincipalChildList().FirstChild()->Style()->GetPseudo() ==
         nsCSSAnonBoxes::table() ||
       aFrame->PrincipalChildList().FirstChild()->Style()->GetPseudo() ==
         nsCSSAnonBoxes::inlineTable())));
}

static bool
IsRubyPseudo(nsIFrame* aFrame)
{
  return RubyUtils::IsRubyPseudo(aFrame->Style()->GetPseudo());
}

static bool
IsTableOrRubyPseudo(nsIFrame* aFrame)
{
  return IsTablePseudo(aFrame) || IsRubyPseudo(aFrame);
}

/* static */
nsCSSFrameConstructor::ParentType
nsCSSFrameConstructor::GetParentType(LayoutFrameType aFrameType)
{
  if (aFrameType == LayoutFrameType::Table) {
    return eTypeTable;
  }
  if (aFrameType == LayoutFrameType::TableRowGroup) {
    return eTypeRowGroup;
  }
  if (aFrameType == LayoutFrameType::TableRow) {
    return eTypeRow;
  }
  if (aFrameType == LayoutFrameType::TableColGroup) {
    return eTypeColGroup;
  }
  if (aFrameType == LayoutFrameType::RubyBaseContainer) {
    return eTypeRubyBaseContainer;
  }
  if (aFrameType == LayoutFrameType::RubyTextContainer) {
    return eTypeRubyTextContainer;
  }
  if (aFrameType == LayoutFrameType::Ruby) {
    return eTypeRuby;
  }

  return eTypeBlock;
}

static nsContainerFrame*
AdjustCaptionParentFrame(nsContainerFrame* aParentFrame)
{
  if (aParentFrame->IsTableFrame()) {
    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(nsContainerFrame*  aParentFrame,
                         const nsIFrame*    aChildFrame,
                         nsContainerFrame** aAdjParentFrame)
{
  *aAdjParentFrame = aParentFrame;
  bool haveCaption = false;

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

void
nsCSSFrameConstructor::AdjustParentFrame(nsContainerFrame**           aParentFrame,
                                         const FrameConstructionData* aFCData,
                                         ComputedStyle*              aComputedStyle)
{
  MOZ_ASSERT(aComputedStyle, "Must have child's style");
  MOZ_ASSERT(aFCData, "Must have frame construction data");

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

  if (tablePart && aComputedStyle->StyleDisplay()->mDisplay ==
      StyleDisplay::TableCaption) {
    *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 (child->IsTableCaption()) {
      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,
                                      nsContainerFrame*        aParentFrame,
                                      const nsStyleDisplay*    aDisplay,
                                      nsFrameItems&            aFrameItems)
{
  MOZ_ASSERT(aDisplay->mDisplay == StyleDisplay::Table ||
             aDisplay->mDisplay == StyleDisplay::InlineTable,
             "Unexpected call");

  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;
  const bool isMathMLContent = content->IsMathMLElement();

  // create the pseudo SC for the table wrapper as a child of the inner SC
  RefPtr<ComputedStyle> outerComputedStyle;
  outerComputedStyle = mPresShell->StyleSet()->
    ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::tableWrapper(),
                                       computedStyle);

  // Create the table wrapper frame which holds the caption and inner table frame
  nsContainerFrame* newFrame;
  if (isMathMLContent)
    newFrame = NS_NewMathMLmtableOuterFrame(mPresShell, outerComputedStyle);
  else
    newFrame = NS_NewTableWrapperFrame(mPresShell, outerComputedStyle);

  nsContainerFrame* geometricParent =
    aState.GetGeometricParent(*outerComputedStyle->StyleDisplay(),
                              aParentFrame);

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

  // Create the inner table frame
  nsContainerFrame* innerFrame;
  if (isMathMLContent)
    innerFrame = NS_NewMathMLmtableFrame(mPresShell, computedStyle);
  else
    innerFrame = NS_NewTableFrame(mPresShell, computedStyle);

  InitAndRestoreFrame(aState, content, newFrame, innerFrame);
  innerFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

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

  aState.AddChild(newFrame, aFrameItems, content, 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 = outerComputedStyle->StyleDisplay();

  // Mark the table frame as an absolute container if needed
  newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  if (display->IsAbsPosContainingBlock(newFrame)) {
    aState.PushAbsoluteContainingBlock(newFrame, newFrame, absoluteSaveState);
  }
  if (aItem.mFCData->mBits & FCDATA_USE_CHILD_ITEMS) {
    ConstructFramesFromItemList(aState, aItem.mChildItems,
                                innerFrame,
                                aItem.mFCData->mBits & FCDATA_IS_WRAPPER_ANON_BOX,
                                childItems);
  } else {
    ProcessChildren(aState, content, computedStyle, 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 table wrapper frame's secondary childlist lists
  if (captionItems.NotEmpty()) {
    newFrame->SetInitialChildList(nsIFrame::kCaptionList, captionItems);
  }

  return newFrame;
}

static void
MakeTablePartAbsoluteContainingBlockIfNeeded(nsFrameConstructorState&     aState,
                                             const nsStyleDisplay*        aDisplay,
                                             nsFrameConstructorSaveState& aAbsSaveState,
                                             nsContainerFrame*            aFrame)
{
  // If we're positioned, then we need to become an absolute containing block
  // for any absolutely positioned children and register for post-reflow fixup.
  //
  // Note that usually if a frame type can be an absolute containing block, we
  // always set NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN, whether it actually is or not.
  // However, in this case flag serves the additional purpose of indicating that
  // the frame was registered with its table frame. This allows us to avoid the
  // overhead of unregistering the frame in most cases.
  if (aDisplay->IsAbsPosContainingBlock(aFrame)) {
    aFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
    aState.PushAbsoluteContainingBlock(aFrame, aFrame, aAbsSaveState);
    nsTableFrame::RegisterPositionedTablePart(aFrame);
  }
}

nsIFrame*
nsCSSFrameConstructor::ConstructTableRowOrRowGroup(nsFrameConstructorState& aState,
                                                   FrameConstructionItem&   aItem,
                                                   nsContainerFrame*        aParentFrame,
                                                   const nsStyleDisplay*    aDisplay,
                                                   nsFrameItems&            aFrameItems)
{
  MOZ_ASSERT(aDisplay->mDisplay == StyleDisplay::TableRow ||
             aDisplay->mDisplay == StyleDisplay::TableRowGroup ||
             aDisplay->mDisplay == StyleDisplay::TableFooterGroup ||
             aDisplay->mDisplay == StyleDisplay::TableHeaderGroup,
             "Not a row or row group");
  MOZ_ASSERT(aItem.mComputedStyle->StyleDisplay() == aDisplay,
             "Display style doesn't match style");
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  nsContainerFrame* newFrame;
  if (aDisplay->mDisplay == StyleDisplay::TableRow) {
    if (content->IsMathMLElement())
      newFrame = NS_NewMathMLmtrFrame(mPresShell, computedStyle);
    else
      newFrame = NS_NewTableRowFrame(mPresShell, computedStyle);
  } else {
    newFrame = NS_NewTableRowGroupFrame(mPresShell, computedStyle);
  }

  InitAndRestoreFrame(aState, content, aParentFrame, newFrame);

  nsFrameConstructorSaveState absoluteSaveState;
  MakeTablePartAbsoluteContainingBlockIfNeeded(aState, aDisplay,
                                               absoluteSaveState,
                                               newFrame);

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

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

nsIFrame*
nsCSSFrameConstructor::ConstructTableCol(nsFrameConstructorState& aState,
                                         FrameConstructionItem&   aItem,
                                         nsContainerFrame*        aParentFrame,
                                         const nsStyleDisplay*    aStyleDisplay,
                                         nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

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

  NS_ASSERTION(colFrame->Style() == computedStyle, "Unexpected style");

  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, computedStyle);
    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,
                                          nsContainerFrame*        aParentFrame,
                                          const nsStyleDisplay*    aDisplay,
                                          nsFrameItems&            aFrameItems)
{
  MOZ_ASSERT(aDisplay->mDisplay == StyleDisplay::TableCell,
             "Unexpected call");

  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;
  const bool isMathMLContent = content->IsMathMLElement();

  nsTableFrame* tableFrame =
    static_cast<nsTableRowFrame*>(aParentFrame)->GetTableFrame();
  nsContainerFrame* 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 (isMathMLContent && !tableFrame->IsBorderCollapse()) {
    newFrame = NS_NewMathMLmtdFrame(mPresShell, computedStyle, tableFrame);
  } 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, computedStyle, tableFrame);
  }

  // Initialize the table cell frame
  InitAndRestoreFrame(aState, content, aParentFrame, newFrame);
  newFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

  // Resolve pseudo style and initialize the body cell frame
  RefPtr<ComputedStyle> innerPseudoStyle;
  innerPseudoStyle = mPresShell->StyleSet()->
    ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::cellContent(),
                                       computedStyle);

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

  InitAndRestoreFrame(aState, content, newFrame, cellInnerFrame);

  nsFrameConstructorSaveState absoluteSaveState;
  MakeTablePartAbsoluteContainingBlockIfNeeded(aState, aDisplay,
                                               absoluteSaveState,
                                               newFrame);

  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,
                                aItem.mFCData->mBits & FCDATA_IS_WRAPPER_ANON_BOX,
                                childItems);
  } else {
    // Process the child content
    ProcessChildren(aState, content, computedStyle, 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.
  MOZ_ASSERT(!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 CreateNeededPseudoContainers 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 &&
       (!aParentFrame->IsFrameOfType(nsIFrame::eExcludesIgnorableWhitespace) ||
        aParentFrame->IsGeneratedContentFrame())) ||
      !aChildContent->IsText()) {
    return true;
  }

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

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

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

  // Resolve a new style for the viewport since it may be affected by a new root
  // element style (e.g. a propagated 'direction').
  //
  // @see ComputedStyle::ApplyStyleFixups
  {
    RefPtr<ComputedStyle> sc = mPresShell->StyleSet()->
      ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::viewport(), nullptr);
    GetRootFrame()->SetComputedStyleWithoutNotification(sc);
  }

  // Make sure to call UpdateViewportScrollStylesOverride before
  // SetUpDocElementContainingBlock, since it sets up our scrollbar state
  // properly.
  DebugOnly<nsIContent*> propagatedScrollFrom;
  if (nsPresContext* presContext = mPresShell->GetPresContext()) {
    propagatedScrollFrom = presContext->UpdateViewportScrollStylesOverride();
  }

  SetUpDocElementContainingBlock(aDocElement);

  NS_ASSERTION(mDocElementContainingBlock, "Should have parent by now");
  nsFrameConstructorState state(mPresShell,
                                GetAbsoluteContainingBlock(mDocElementContainingBlock, FIXED_POS),
                                nullptr,
                                nullptr, do_AddRef(aFrameState));

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

  // --------- CREATE AREA OR BOX FRAME -------
  ServoStyleSet* set = mPresShell->StyleSet();
  // Ensure the document element is styled at this point.
  if (!aDocElement->HasServoData()) {
    // NOTE(emilio): If the root has a non-null binding, we'll stop at the
    // document element and won't process any children, loading the bindings
    // (or failing to do so) will take care of the rest.
    set->StyleNewSubtree(aDocElement);
  }

  RefPtr<ComputedStyle> computedStyle =
    mPresShell->StyleSet()->ResolveServoStyle(*aDocElement);

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

  // Ensure that our XBL bindings are installed.
  //
  // FIXME(emilio): Can we remove support for bindings on the root?
  if (display->mBinding) {
    // Get the XBL loader.
    nsresult rv;
    bool resolveStyle;

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

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

    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) {
      computedStyle = mPresShell->StyleSet()->ResolveServoStyle(*aDocElement);
      display = computedStyle->StyleDisplay();
    }
  }

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

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

  if (MOZ_UNLIKELY(display->mDisplay == StyleDisplay::None)) {
    return nullptr;
  }

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

  nsFrameConstructorSaveState docElementContainingBlockAbsoluteSaveState;
  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,
                                      docElementContainingBlockAbsoluteSaveState);
  }

  // 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.
  nsContainerFrame* contentFrame;
  nsIFrame* newFrame;
  bool processChildren = false;

  nsFrameConstructorSaveState absoluteSaveState;

  // Check whether we need to build a XUL box or SVG root frame
#ifdef MOZ_XUL
  if (aDocElement->IsXULElement()) {
    contentFrame = NS_NewDocElementBoxFrame(mPresShell, computedStyle);
    InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                        contentFrame);
    newFrame = contentFrame;
    processChildren = true;
  }
  else
#endif
  if (aDocElement->IsSVGElement()) {
    if (!aDocElement->IsSVGElement(nsGkAtoms::svg)) {
      return nullptr;
    }
    // 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);
    AutoFrameConstructionItem item(this, &rootSVGData, aDocElement,
                                   nullptr, do_AddRef(computedStyle), true);

    nsFrameItems frameItems;
    contentFrame = static_cast<nsContainerFrame*>(
      ConstructOuterSVG(state, item, mDocElementContainingBlock,
                        computedStyle->StyleDisplay(),
                        frameItems));
    newFrame = frameItems.FirstChild();
    NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
  } else if (display->mDisplay == StyleDisplay::Flex ||
             display->mDisplay == StyleDisplay::WebkitBox ||
             (StaticPrefs::layout_css_emulate_moz_box_with_flex() &&
              display->mDisplay == StyleDisplay::MozBox)) {
    contentFrame = NS_NewFlexContainerFrame(mPresShell, computedStyle);
    InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                        contentFrame);
    newFrame = contentFrame;
    processChildren = true;

    newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
    if (display->IsAbsPosContainingBlock(newFrame)) {
      state.PushAbsoluteContainingBlock(contentFrame, newFrame,
                                        absoluteSaveState);
    }

  } else if (display->mDisplay == StyleDisplay::Grid) {
    contentFrame = NS_NewGridContainerFrame(mPresShell, computedStyle);
    InitAndRestoreFrame(state, aDocElement, mDocElementContainingBlock,
                        contentFrame);
    newFrame = contentFrame;
    processChildren = true;

    newFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
    if (display->IsAbsPosContainingBlock(newFrame)) {
      state.PushAbsoluteContainingBlock(contentFrame, newFrame,
                                        absoluteSaveState);
    }
  } else if (display->mDisplay == StyleDisplay::Table) {
    // 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);
    AutoFrameConstructionItem item(this, &rootTableData, aDocElement,
                                   nullptr, do_AddRef(computedStyle), true);

    nsFrameItems frameItems;
    // if the document is a table then just populate it.
    contentFrame = static_cast<nsContainerFrame*>(
      ConstructTable(state, item, mDocElementContainingBlock,
                     computedStyle->StyleDisplay(),
                     frameItems));
    newFrame = frameItems.FirstChild();
    NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
  } else {
    MOZ_ASSERT(display->mDisplay == StyleDisplay::Block ||
               display->mDisplay == StyleDisplay::FlowRoot,
               "Unhandled display type for root element");
    contentFrame = NS_NewBlockFormattingContext(mPresShell, computedStyle);
    nsFrameItems frameItems;
    // Use a null PendingBinding, since our binding is not in fact pending.
    ConstructBlock(state, aDocElement,
                   state.GetGeometricParent(*display,
                                            mDocElementContainingBlock),
                   mDocElementContainingBlock, computedStyle,
                   &contentFrame, frameItems,
                   display->IsAbsPosContainingBlock(contentFrame) ? contentFrame : nullptr,
                   nullptr);
    newFrame = frameItems.FirstChild();
    NS_ASSERTION(frameItems.OnlyChild(), "multiple root element frames");
  }

  MOZ_ASSERT(newFrame);
  MOZ_ASSERT(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.
  contentFrame->GetParentComputedStyle(&mRootElementStyleFrame);
  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, computedStyle, contentFrame, true,
                    childItems, false, nullptr);

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

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

  SetInitialSingleChild(mDocElementContainingBlock, newFrame);

  // Create frames for anonymous contents if there is a canvas frame.
  if (mDocElementContainingBlock->IsCanvasFrame()) {
    ConstructAnonymousContentForCanvas(state, mDocElementContainingBlock,
                                       aDocElement);
  }

  return newFrame;
}


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

  ServoStyleSet* styleSet = mPresShell->StyleSet();

  // --------- BUILD VIEWPORT -----------
  RefPtr<ComputedStyle> viewportPseudoStyle =
    styleSet->ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::viewport(),
                                                 nullptr);
  ViewportFrame* 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);

  viewportFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

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

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

  // Make it an absolute container for fixed-pos elements
  viewportFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  viewportFrame->MarkAsAbsoluteContainingBlock();

  return viewportFrame;
}

void
nsCSSFrameConstructor::SetUpDocElementContainingBlock(nsIContent* aDocElement)
{
  MOZ_ASSERT(aDocElement, "No element?");
  MOZ_ASSERT(!aDocElement->GetParent(), "Not root content?");
  MOZ_ASSERT(aDocElement->GetUncomposedDoc(), "Not in a document?");
  MOZ_ASSERT(aDocElement->GetUncomposedDoc()->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,
                                nsTableWrapperFrame, nsPlaceholderFrame)

  Galley presentation, XUL

      ViewportFrame [fixed-cb]
        nsRootBoxFrame
          root element frame (nsDocElementBoxFrame)

  Print presentation, non-XUL

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

  Print-preview presentation, non-XUL

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

    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();
  nsContainerFrame* viewportFrame = static_cast<nsContainerFrame*>(GetRootFrame());
  ComputedStyle* viewportPseudoStyle = viewportFrame->Style();

  nsContainerFrame* rootFrame = nullptr;
  nsAtom* rootPseudo;

  if (!isPaginated) {
#ifdef MOZ_XUL
    if (aDocElement->IsXULElement())
    {
      // 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();
    rootFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
  }


  // --------- 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?

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

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

  // 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");

  nsContainerFrame* newFrame = rootFrame;
  RefPtr<ComputedStyle> 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.
  nsContainerFrame* parentFrame = viewportFrame;

  ServoStyleSet* styleSet = mPresShell->StyleSet();
  // If paginated, make sure we don't put scrollbars in
  if (!isScrollable) {
    rootPseudoStyle =
      styleSet->ResolveInheritingAnonymousBoxStyle(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
      RefPtr<ComputedStyle>  computedStyle =
        styleSet->ResolveInheritingAnonymousBoxStyle(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,
                                                  computedStyle,
                                                  viewportFrame,
                                                  rootPseudo,
                                                  true,
                                                  newFrame);
      parentFrame = newFrame;
  }

  rootFrame->SetComputedStyleWithoutNotification(rootPseudoStyle);
  rootFrame->Init(aDocElement, parentFrame, nullptr);

  if (isScrollable) {
    FinishBuildingScrollFrame(parentFrame, rootFrame);
  }

  if (isPaginated) {
    // Create the first page
    // Set the initial child lists
    nsContainerFrame* canvasFrame;
    nsContainerFrame* pageFrame =
      ConstructPageFrame(mPresShell, rootFrame, nullptr, canvasFrame);
    pageFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
    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);
  }
}

void
nsCSSFrameConstructor::ConstructAnonymousContentForCanvas(nsFrameConstructorState& aState,
                                                          nsIFrame* aFrame,
                                                          nsIContent* aDocElement)
{
  NS_ASSERTION(aFrame->IsCanvasFrame(), "aFrame should be canvas frame!");

  AutoTArray<nsIAnonymousContentCreator::ContentInfo, 4> anonymousItems;
  GetAnonymousContent(aDocElement, aFrame, anonymousItems);
  if (anonymousItems.IsEmpty()) {
    return;
  }

  AutoFrameConstructionItemList itemsToConstruct(this);
  nsContainerFrame* frameAsContainer = do_QueryFrame(aFrame);
  AddFCItemsForAnonymousContent(aState, frameAsContainer, anonymousItems, itemsToConstruct);

  nsFrameItems frameItems;
  ConstructFramesFromItemList(aState, itemsToConstruct, frameAsContainer,
                              /* aParentIsWrapperAnonBox = */ false,
                              frameItems);
  frameAsContainer->AppendFrames(kPrincipalList, frameItems);
}

nsContainerFrame*
nsCSSFrameConstructor::ConstructPageFrame(nsIPresShell*  aPresShell,
                                          nsContainerFrame* aParentFrame,
                                          nsIFrame*      aPrevPageFrame,
                                          nsContainerFrame*& aCanvasFrame)
{
  ComputedStyle* parentComputedStyle = aParentFrame->Style();
  ServoStyleSet* styleSet = aPresShell->StyleSet();

  RefPtr<ComputedStyle> pagePseudoStyle;
  pagePseudoStyle =
    styleSet->ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::page(),
                                                 parentComputedStyle);

  nsContainerFrame* 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);

  RefPtr<ComputedStyle> pageContentPseudoStyle;
  pageContentPseudoStyle =
    styleSet->ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::pageContent(),
                                                 pagePseudoStyle);

  nsContainerFrame* 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->PrincipalChildList().FirstChild();
    NS_ASSERTION(prevPageContentFrame, "missing page content frame");
  }
  pageContentFrame->Init(nullptr, pageFrame, prevPageContentFrame);
  if (!prevPageContentFrame) {
    pageContentFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);
  }
  SetInitialSingleChild(pageFrame, pageContentFrame);
  // Make it an absolute container for fixed-pos elements
  pageContentFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  pageContentFrame->MarkAsAbsoluteContainingBlock();

  RefPtr<ComputedStyle> canvasPseudoStyle;
  canvasPseudoStyle =
    styleSet->ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::canvas(),
                                                 pageContentPseudoStyle);

  aCanvasFrame = NS_NewCanvasFrame(aPresShell, canvasPseudoStyle);

  nsIFrame* prevCanvasFrame = nullptr;
  if (prevPageContentFrame) {
    prevCanvasFrame = prevPageContentFrame->PrincipalChildList().FirstChild();
    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,
                                                 nsContainerFrame* aParentFrame,
                                                 nsIFrame*         aPrevInFlow,
                                                 nsFrameState      aTypeBit)
{
  RefPtr<ComputedStyle> placeholderStyle = aPresShell->StyleSet()->
    ResolveStyleForPlaceholder();

  // The placeholder frame gets a pseudo style.
  nsPlaceholderFrame* placeholderFrame =
    NS_NewPlaceholderFrame(aPresShell, placeholderStyle, aTypeBit);

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

  // Associate the placeholder/out-of-flow with each other.
  placeholderFrame->SetOutOfFlowFrame(aFrame);
  aFrame->SetProperty(nsIFrame::PlaceholderFrameProperty(), placeholderFrame);

  aFrame->AddStateBits(NS_FRAME_OUT_OF_FLOW);

  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)
{
  MOZ_ASSERT(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,
                                            nsContainerFrame*        aParentFrame,
                                            const nsStyleDisplay*    aStyleDisplay,
                                            nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  // Construct a frame-based listbox or combobox
  dom::HTMLSelectElement* sel = dom::HTMLSelectElement::FromNode(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.
    nsFrameState flags = NS_BLOCK_FLOAT_MGR;
    nsComboboxControlFrame* comboboxFrame =
      NS_NewComboboxControlFrame(mPresShell, computedStyle, 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);

    comboboxFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

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

    // Resolve pseudo element style for the dropdown list
    RefPtr<ComputedStyle> listStyle;
    listStyle = mPresShell->StyleSet()->
      ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::dropDownList(),
                                         computedStyle);

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

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

    if (!nsLayoutUtils::IsContentSelectEnabled()) {
      // TODO(kuoe0) Remove this assertion when content-select is shipped.
      NS_ASSERTION(!listFrame->IsAbsPosContainingBlock(),
                   "Ended up with positioned dropdown list somehow.");
    }
    NS_ASSERTION(!listFrame->IsFloating(),
                 "Ended up with floating dropdown list somehow.");

    // child frames of combobox frame
    nsFrameItems childItems;

    // Initialize the scroll frame positioned. Note that it is NOT
    // initialized as absolutely positioned.
    nsContainerFrame* scrolledFrame =
      NS_NewSelectsAreaFrame(mPresShell, computedStyle, flags);

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

    if (!nsLayoutUtils::IsContentSelectEnabled()) {
      // TODO(kuoe0) Remove this assertion when content-select is shipped.
      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).
    //
    // nsComboboxControlFrame needs special frame creation behavior for its first
    // piece of anonymous content, which means that we can't take the normal
    // ProcessChildren path.
    AutoTArray<nsIAnonymousContentCreator::ContentInfo, 2> newAnonymousItems;
    DebugOnly<nsresult> rv = GetAnonymousContent(content, comboboxFrame, newAnonymousItems);
    MOZ_ASSERT(NS_SUCCEEDED(rv));
    MOZ_ASSERT(newAnonymousItems.Length() == 2);

    // Manually create a frame for the special NAC.
    MOZ_ASSERT(newAnonymousItems[0].mContent == comboboxFrame->GetDisplayNode());
    newAnonymousItems.RemoveElementAt(0);
    nsIFrame* customFrame = comboboxFrame->CreateFrameForDisplayNode();
    MOZ_ASSERT(customFrame);
    customFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
    childItems.AddChild(customFrame);

    // The other piece of NAC can take the normal path.
    AutoFrameConstructionItemList fcItems(this);
    AddFCItemsForAnonymousContent(aState, comboboxFrame, newAnonymousItems,
                                  fcItems);
    ConstructFramesFromItemList(aState, fcItems, comboboxFrame,
                                /* aParentIsWrapperAnonBox = */ false,
                                childItems);

    comboboxFrame->SetInitialChildList(kPrincipalList, childItems);

    if (!nsLayoutUtils::IsContentSelectEnabled()) {
      // 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
  nsContainerFrame* listFrame =
    NS_NewListControlFrame(mPresShell, computedStyle);

  nsContainerFrame* scrolledFrame = NS_NewSelectsAreaFrame(
      mPresShell, computedStyle, NS_BLOCK_FLOAT_MGR);

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

  InitializeSelectFrame(aState, listFrame, scrolledFrame, content,
                        aParentFrame, computedStyle, 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.
 */
void
nsCSSFrameConstructor::InitializeSelectFrame(nsFrameConstructorState& aState,
                                             nsContainerFrame*        scrollFrame,
                                             nsContainerFrame*        scrolledFrame,
                                             nsIContent*              aContent,
                                             nsContainerFrame*        aParentFrame,
                                             ComputedStyle*          aComputedStyle,
                                             bool                     aBuildCombobox,
                                             PendingBinding*          aPendingBinding,
                                             nsFrameItems&            aFrameItems)
{
  // Initialize it
  nsContainerFrame* geometricParent =
    aState.GetGeometricParent(*aComputedStyle->StyleDisplay(), 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.

  scrollFrame->Init(aContent, geometricParent, nullptr);

  if (!aBuildCombobox || nsLayoutUtils::IsContentSelectEnabled()) {
    aState.AddChild(scrollFrame, aFrameItems, aContent, aParentFrame);
  }

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

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

  // Process children
  nsFrameItems                childItems;

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

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

nsIFrame*
nsCSSFrameConstructor::ConstructFieldSetFrame(nsFrameConstructorState& aState,
                                              FrameConstructionItem&   aItem,
                                              nsContainerFrame*        aParentFrame,
                                              const nsStyleDisplay*    aStyleDisplay,
                                              nsFrameItems&            aFrameItems)
{
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  nsContainerFrame* fieldsetFrame =
    NS_NewFieldSetFrame(mPresShell, computedStyle);

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

  fieldsetFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

  // Resolve style and initialize the frame
  RefPtr<ComputedStyle> fieldsetContentStyle;
  fieldsetContentStyle = mPresShell->StyleSet()->
    ResolveInheritingAnonymousBoxStyle(nsCSSAnonBoxes::fieldsetContent(),
                                       computedStyle);

  const nsStyleDisplay* fieldsetContentDisplay = fieldsetContentStyle->StyleDisplay();
  bool isScrollable = fieldsetContentDisplay->IsScrollableOverflow();
  nsContainerFrame* scrollFrame = nullptr;
  if (isScrollable) {
    fieldsetContentStyle =
      BeginBuildingScrollFrame(aState, content, fieldsetContentStyle,
                               fieldsetFrame, nsCSSAnonBoxes::scrolledContent(),
                               false, scrollFrame);
  }

  nsContainerFrame* absPosContainer = nullptr;
  if (fieldsetFrame->IsAbsPosContainingBlock()) {
    absPosContainer = fieldsetFrame;
  }

  // Create the inner ::-moz-fieldset-content frame.
  nsContainerFrame* contentFrameTop;
  nsContainerFrame* contentFrame;
  auto parent = scrollFrame ? scrollFrame : fieldsetFrame;
  switch (fieldsetContentDisplay->mDisplay) {
    case StyleDisplay::Flex:
      contentFrame = NS_NewFlexContainerFrame(mPresShell, fieldsetContentStyle);
      InitAndRestoreFrame(aState, content, parent, contentFrame);
      contentFrameTop = contentFrame;
      break;
    case StyleDisplay::Grid:
      contentFrame = NS_NewGridContainerFrame(mPresShell, fieldsetContentStyle);
      InitAndRestoreFrame(aState, content, parent, contentFrame);
      contentFrameTop = contentFrame;
      break;
    default: {
      MOZ_ASSERT(fieldsetContentDisplay->mDisplay == StyleDisplay::Block,
                 "bug in StyleAdjuster::adjust_for_fieldset_content?");

      contentFrame = NS_NewBlockFormattingContext(mPresShell, fieldsetContentStyle);
      contentFrameTop =
        InitAndWrapInColumnSetFrameIfNeeded(aState, content, parent,
                                            contentFrame, fieldsetContentStyle);
      if (contentFrame != contentFrameTop) {
        // contentFrame is wrapped in nsColumnSetFrame.
        if (absPosContainer) {
          absPosContainer = contentFrameTop;
        }
      }

      break;
    }
  }

  aState.AddChild(fieldsetFrame, aFrameItems, content, aParentFrame);

  // Process children
  nsFrameConstructorSaveState absoluteSaveState;
  nsFrameItems                childItems;

  contentFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  if (absPosContainer) {
    aState.PushAbsoluteContainingBlock(contentFrame, absPosContainer, absoluteSaveState);
  }

  ProcessChildren(aState, content, computedStyle, contentFrame, true,
                  childItems, true, aItem.mPendingBinding);

  nsFrameItems fieldsetKids;
  fieldsetKids.AddChild(scrollFrame ? scrollFrame : contentFrameTop);

  for (nsFrameList::Enumerator e(childItems); !e.AtEnd(); e.Next()) {
    nsIFrame* child = e.get();
    nsContainerFrame* cif = child->GetContentInsertionFrame();
    if (cif && cif->IsLegendFrame()) {
      // 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(fieldsetFrame, nullptr, child);
      if (scrollFrame) {
        StickyScrollContainer::NotifyReparentedFrameAcrossScrollFrameBoundary(
            child, contentFrame);
      }
      break;
    }
  }

  if (isScrollable) {
    FinishBuildingScrollFrame(scrollFrame, contentFrameTop);
  }

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

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

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

nsIFrame*
nsCSSFrameConstructor::ConstructDetailsFrame(nsFrameConstructorState& aState,
                                             FrameConstructionItem& aItem,
                                             nsContainerFrame* aParentFrame,
                                             const nsStyleDisplay* aStyleDisplay,
                                             nsFrameItems& aFrameItems)
{
  if (!aStyleDisplay->IsScrollableOverflow()) {
    return ConstructNonScrollableBlockWithConstructor(aState, aItem, aParentFrame,
                                                      aStyleDisplay, aFrameItems,
                                                      NS_NewDetailsFrame);
  }

  // Build a scroll frame to wrap details frame if necessary.
  return ConstructScrollableBlockWithConstructor(aState, aItem, aParentFrame,
                                                 aStyleDisplay, aFrameItems,
                                                 NS_NewDetailsFrame);
}

static nsIFrame*
FindAncestorWithGeneratedContentPseudo(nsIFrame* aFrame)
{
  for (nsIFrame* f = aFrame->GetParent(); f; f = f->GetParent()) {
    NS_ASSERTION(f->IsGeneratedContentFrame(),
                 "should not have exited generated content");
    nsAtom* pseudo = f->Style()->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(const Text& aTextContent,
                                    nsIFrame* aParentFrame)
{
  if (aParentFrame && IsFrameForSVG(aParentFrame)) {
    nsIFrame* ancestorFrame =
      nsSVGUtils::GetFirstNonAAncestorFrame(aParentFrame);
    if (!ancestorFrame || !nsSVGUtils::IsInSVGTextSubtree(ancestorFrame)) {
      return nullptr;
    }

    // Don't render stuff in display: contents / Shadow DOM subtrees, because
    // TextCorrespondenceRecorder in the SVG text code doesn't really know how
    // to deal with it. This kinda sucks. :(
    if (aParentFrame->GetContent() != aTextContent.GetParent()) {
      return nullptr;
    }

    static const FrameConstructionData sSVGTextData =
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT | FCDATA_IS_SVG_TEXT,
                  NS_NewTextFrame);
    return &sSVGTextData;
  }

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

void
nsCSSFrameConstructor::ConstructTextFrame(const FrameConstructionData* aData,
                                          nsFrameConstructorState& aState,
                                          nsIContent*              aContent,
                                          nsContainerFrame*        aParentFrame,
                                          ComputedStyle*          aComputedStyle,
                                          nsFrameItems&            aFrameItems)
{
  MOZ_ASSERT(aData, "Must have frame construction data");

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

  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,
                                     const Element& aElement,
                                     ComputedStyle& aComputedStyle,
                                     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, aComputedStyle);
      }

      return data;
    }
  }

  return nullptr;
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDataByTag(nsAtom* aTag,
                                     const Element& aElement,
                                     ComputedStyle& aStyle,
                                     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, aStyle);
      }

      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 bool
IsFrameForFieldSet(nsIFrame* aFrame)
{
  nsAtom* pseudo = aFrame->Style()->GetPseudo();
  if (pseudo == nsCSSAnonBoxes::fieldsetContent() ||
      pseudo == nsCSSAnonBoxes::scrolledContent() ||
      pseudo == nsCSSAnonBoxes::columnContent()) {
    return IsFrameForFieldSet(aFrame->GetParent());
  }
  return aFrame->IsFieldSetFrame();
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindHTMLData(const Element& aElement,
                                    nsIFrame* aParentFrame,
                                    ComputedStyle& aStyle)
{
  MOZ_ASSERT(aElement.IsHTMLElement());

  nsAtom* tag = aElement.NodeInfo()->NameAtom();
  NS_ASSERTION(!aParentFrame ||
               aParentFrame->Style()->GetPseudo() !=
                 nsCSSAnonBoxes::fieldsetContent() ||
               aParentFrame->GetParent()->IsFieldSetFrame(),
               "Unexpected parent for fieldset content anon box");
  if (tag == nsGkAtoms::legend &&
      (!aParentFrame || !IsFrameForFieldSet(aParentFrame) ||
       aStyle.StyleDisplay()->IsFloatingStyle() ||
       aStyle.StyleDisplay()->IsAbsolutelyPositionedStyle())) {
    // <legend> is only special inside fieldset, we only check the frame tree
    // parent because the content tree parent may not be a <fieldset> due to
    // display:contents, Shadow DOM, or XBL. For floated or absolutely
    // positioned legends we want to construct by display type and
    // not do special legend stuff.
    return nullptr;
  }

  static const FrameConstructionDataByTag sHTMLData[] = {
    SIMPLE_TAG_CHAIN(img, nsCSSFrameConstructor::FindImgData),
    SIMPLE_TAG_CHAIN(mozgeneratedcontentimage,
                     nsCSSFrameConstructor::FindGeneratedImageData),
    { 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(embed, nsCSSFrameConstructor::FindObjectData),
    COMPLEX_TAG_CREATE(fieldset,
                       &nsCSSFrameConstructor::ConstructFieldSetFrame),
    { nsGkAtoms::legend,
      FCDATA_DECL(FCDATA_ALLOW_BLOCK_STYLES |
                  FCDATA_MAY_NEED_SCROLLFRAME |
                  FCDATA_MAY_NEED_BULLET,
                  NS_NewLegendFrame) },
    SIMPLE_TAG_CREATE(frameset, NS_NewHTMLFramesetFrame),
    SIMPLE_TAG_CREATE(iframe, NS_NewSubDocumentFrame),
    { nsGkAtoms::button,
      FCDATA_WITH_WRAPPING_BLOCK(FCDATA_ALLOW_BLOCK_STYLES |
                                 FCDATA_ALLOW_GRID_FLEX_COLUMNSET,
                                 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),
    COMPLEX_TAG_CREATE(details, &nsCSSFrameConstructor::ConstructDetailsFrame)
  };

  return FindDataByTag(tag, aElement, aStyle, sHTMLData, ArrayLength(sHTMLData));
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindGeneratedImageData(const Element& aElement,
                                              ComputedStyle&)
{
  if (!aElement.IsInNativeAnonymousSubtree()) {
    return nullptr;
  }

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

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

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

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

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

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindInputData(const Element& aElement,
                                     ComputedStyle& aStyle)
{
  static const FrameConstructionDataByInt sInputData[] = {
    SIMPLE_INT_CREATE(NS_FORM_INPUT_CHECKBOX, NS_NewCheckboxRadioFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_RADIO, NS_NewCheckboxRadioFrame),
    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),
    { NS_FORM_INPUT_COLOR,
      FCDATA_WITH_WRAPPING_BLOCK(0, NS_NewColorControlFrame,
                                 nsCSSAnonBoxes::buttonContent()) },
    // TODO: this is temporary until a frame is written: bug 635240.
    SIMPLE_INT_CREATE(NS_FORM_INPUT_NUMBER, NS_NewNumberControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_TIME, NS_NewDateTimeControlFrame),
    SIMPLE_INT_CREATE(NS_FORM_INPUT_DATE, NS_NewDateTimeControlFrame),
    // TODO: this is temporary until a frame is written: bug 888320
    SIMPLE_INT_CREATE(NS_FORM_INPUT_MONTH, NS_NewTextControlFrame),
    // TODO: this is temporary until a frame is written: bug 888320
    SIMPLE_INT_CREATE(NS_FORM_INPUT_WEEK, NS_NewTextControlFrame),
    // TODO: this is temporary until a frame is written: bug 888320
    SIMPLE_INT_CREATE(NS_FORM_INPUT_DATETIME_LOCAL, 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).
  };


  auto controlType = HTMLInputElement::FromNode(aElement)->ControlType();

  // radio and checkbox inputs with appearance:none should be constructed
  // by display type.  (Note that we're not checking that appearance is
  // not (respectively) StyleAppearance::Radio and StyleAppearance::Checkbox.)
  if ((controlType == NS_FORM_INPUT_CHECKBOX ||
       controlType == NS_FORM_INPUT_RADIO) &&
      !aStyle.StyleDisplay()->HasAppearance()) {
    return nullptr;
  }

  return FindDataByInt(controlType, aElement, aStyle,
                       sInputData, ArrayLength(sInputData));
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindObjectData(const Element& aElement,
                                      ComputedStyle& aStyle)
{
  // 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(const_cast<Element*>(&aElement));
    NS_ASSERTION(objContent,
                 "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),
    // Fake plugin handlers load as documents
    SIMPLE_INT_CREATE(nsIObjectLoadingContent::TYPE_FAKE_PLUGIN,
                      NS_NewSubDocumentFrame)
    // Nothing for TYPE_NULL so we'll construct frames by display there
  };

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

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindCanvasData(const Element& aElement,
                                      ComputedStyle& aStyle)
{
  // 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,
                                                      nsContainerFrame* 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");
  MOZ_ASSERT(!(bits & FCDATA_IS_WRAPPER_ANON_BOX) ||
             (bits & FCDATA_USE_CHILD_ITEMS),
             "Wrapper anon boxes should always have FCDATA_USE_CHILD_ITEMS");

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

  nsIContent* const content = aItem.mContent;
  nsIFrame* newFrame;
  nsIFrame* primaryFrame;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;
  const nsStyleDisplay* display = computedStyle->StyleDisplay();
  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, computedStyle);

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

    nsContainerFrame* 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()) {
      nsContainerFrame* scrollframe = nullptr;
      BuildScrollFrame(aState, content, computedStyle, newFrame,
                       geometricParent, scrollframe);
      frameToAddToList = scrollframe;
    } else {
      InitAndRestoreFrame(aState, content, geometricParent, newFrame);
      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.
    nsIFrame* maybeAbsoluteContainingBlockStyleFrame = primaryFrame;
    nsIFrame* maybeAbsoluteContainingBlock = newFrame;
    nsIFrame* possiblyLeafFrame = newFrame;
    if (bits & FCDATA_CREATE_BLOCK_WRAPPER_FOR_ALL_KIDS) {
      RefPtr<ComputedStyle> outerSC = mPresShell->StyleSet()->
        ResolveInheritingAnonymousBoxStyle(data->mAnonBoxPseudo, computedStyle);
#ifdef DEBUG
      nsContainerFrame* containerFrame = do_QueryFrame(newFrame);
      MOZ_ASSERT(containerFrame);
#endif
      nsContainerFrame* container = static_cast<nsContainerFrame*>(newFrame);
      nsContainerFrame* outerFrame;
      nsContainerFrame* innerFrame;
      if (bits & FCDATA_ALLOW_GRID_FLEX_COLUMNSET) {
        switch (display->mDisplay) {
          case StyleDisplay::Flex:
          case StyleDisplay::InlineFlex:
            outerFrame = NS_NewFlexContainerFrame(mPresShell, outerSC);
            InitAndRestoreFrame(aState, content, container, outerFrame);
            innerFrame = outerFrame;
            break;
          case StyleDisplay::Grid:
          case StyleDisplay::InlineGrid:
            outerFrame = NS_NewGridContainerFrame(mPresShell, outerSC);
            InitAndRestoreFrame(aState, content, container, outerFrame);
            innerFrame = outerFrame;
            break;
          default: {
            innerFrame = NS_NewBlockFormattingContext(mPresShell, outerSC);
            outerFrame =
              InitAndWrapInColumnSetFrameIfNeeded(aState, content, container,
                                                  innerFrame, outerSC);
            break;
          }
        }
      } else {
        innerFrame = NS_NewBlockFormattingContext(mPresShell, outerSC);
        InitAndRestoreFrame(aState, content, container, innerFrame);
        outerFrame = innerFrame;
      }

      SetInitialSingleChild(container, outerFrame);

      container->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

      // Now figure out whether newFrame or outerFrame should be the
      // absolute container.
      auto outerDisplay = outerSC->StyleDisplay();
      if (outerDisplay->IsAbsPosContainingBlock(outerFrame)) {
        maybeAbsoluteContainingBlock = outerFrame;
        maybeAbsoluteContainingBlockStyleFrame = outerFrame;
        innerFrame->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
      }

      // Our kids should go into the innerFrame.
      newFrame = innerFrame;
    }

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

    nsContainerFrame* newFrameAsContainer = do_QueryFrame(newFrame);
    if (newFrameAsContainer) {
#ifdef MOZ_XUL
      // Icky XUL stuff, sadly

      if (aItem.mIsRootPopupgroup) {
        NS_ASSERTION(nsIPopupContainer::GetPopupContainer(mPresShell) &&
                     nsIPopupContainer::GetPopupContainer(mPresShell)->
                      GetPopupSetFrame() == newFrame,
                     "Unexpected PopupSetFrame");
        aState.mPopupItems.containingBlock = newFrameAsContainer;
        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)) {
        maybeAbsoluteContainingBlock->AddStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
        if (maybeAbsoluteContainingBlockStyleFrame->IsAbsPosContainingBlock()) {
          auto* cf = static_cast<nsContainerFrame*>(maybeAbsoluteContainingBlock);
          aState.PushAbsoluteContainingBlock(cf, maybeAbsoluteContainingBlockStyleFrame, absoluteSaveState);
        }
      }

      if (bits & FCDATA_USE_CHILD_ITEMS) {
        nsFrameConstructorSaveState floatSaveState;

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

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

          childItems.RemoveFrame(f);
          if (wrapFrame) {
            currentBlockItems.AddChild(f);
          } else {
            newItems.AddChild(f);
          }
        }
        FlushAccumulatedBlock(aState, content, newFrameAsContainer,
                              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!
      newFrameAsContainer->SetInitialChildList(kPrincipalList, childItems);

      if (bits & FCDATA_MAY_NEED_BULLET) {
        nsBlockFrame* block = nsLayoutUtils::GetAsBlock(newFrameAsContainer);
        MOZ_ASSERT(block, "FCDATA_MAY_NEED_BULLET should not be set on "
                          "non-block type!");
        CreateBulletFrameForListItemIfNeeded(block);
      }
    }
  }

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

  if (aItem.mIsAnonymousContentCreatorContent) {
    primaryFrame->AddStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT);
  }

  // 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->HasAnyStateBits(NS_FRAME_ANONYMOUSCONTENTCREATOR_CONTENT |
                                      NS_FRAME_GENERATED_CONTENT) &&
        !aItem.mContent->GetPrimaryFrame())) &&
       !(bits & FCDATA_SKIP_FRAMESET)) {
    aItem.mContent->SetPrimaryFrame(primaryFrame);
    ActiveLayerTracker::TransferActivityToFrame(aItem.mContent, primaryFrame);
  }
}

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
  for (nsIContent* child = aNode->GetFirstChild(); child;
       child = child->GetNextSibling()) {
    SetFlagsOnSubtree(child, 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);
  if (NS_FAILED(rv)) {
    // CreateAnonymousContent failed, e.g. because the page has a <use> loop.
    return rv;
  }

  for (const auto& info : aContent) {
    // get our child's content and set its parent to our content
    nsIContent* content = info.mContent;
    content->SetIsNativeAnonymousRoot();

    bool anonContentIsEditable = content->HasFlag(NODE_IS_EDITABLE);

    // If the parent is in a shadow tree, make sure we don't
    // bind with a document because shadow roots and its descendants
    // are not in document.
    nsIDocument* bindDocument =
      aParent->HasFlag(NODE_IS_IN_SHADOW_TREE) ? nullptr : mDocument;
    rv = content->BindToTree(bindDocument, aParent, aParent);
    // 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->IsTextInputFrame(),
                   "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;
    }
  }

  ServoStyleSet* styleSet = mPresShell->StyleSet();
  // Eagerly compute styles for the anonymous content tree.
  for (auto& info : aContent) {
    if (info.mContent->IsElement()) {
      styleSet->StyleNewSubtree(info.mContent->AsElement());
    }
  }

  return NS_OK;
}

static
bool IsXULDisplayType(const nsStyleDisplay* aDisplay)
{
  // -moz-{inline-}box is XUL, unless we're emulating it with flexbox.
  if (!StaticPrefs::layout_css_emulate_moz_box_with_flex() &&
      (aDisplay->mDisplay == StyleDisplay::MozInlineBox ||
       aDisplay->mDisplay == StyleDisplay::MozBox)) {
    return true;
  }

#ifdef MOZ_XUL
  return (aDisplay->mDisplay == StyleDisplay::MozInlineGrid ||
          aDisplay->mDisplay == StyleDisplay::MozInlineStack ||
          aDisplay->mDisplay == StyleDisplay::MozGrid ||
          aDisplay->mDisplay == StyleDisplay::MozStack ||
          aDisplay->mDisplay == StyleDisplay::MozGridGroup ||
          aDisplay->mDisplay == StyleDisplay::MozGridLine ||
          aDisplay->mDisplay == StyleDisplay::MozDeck ||
          aDisplay->mDisplay == StyleDisplay::MozPopup ||
          aDisplay->mDisplay == StyleDisplay::MozGroupbox);
#else
  return false;
#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_DISPLAY_CREATE(_display, _func)      \
  FCDATA_FOR_DISPLAY(_display, SIMPLE_XUL_FCDATA(_func))
#define SCROLLABLE_XUL_DISPLAY_CREATE(_display, _func)                          \
  FCDATA_FOR_DISPLAY(_display, SCROLLABLE_XUL_FCDATA(_func))
#define SCROLLABLE_ABSPOS_CONTAINER_XUL_DISPLAY_CREATE(_display, _func)         \
  FCDATA_FOR_DISPLAY(_display, SCROLLABLE_ABSPOS_CONTAINER_XUL_FCDATA(_func))

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

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULTagData(const Element& aElement,
                                      nsAtom* aTag,
                                      ComputedStyle& aStyle)
{
  MOZ_ASSERT(aElement.IsXULElement());

  static const FrameConstructionDataByTag sXULTagData[] = {
#ifdef MOZ_XUL
    SCROLLABLE_XUL_CREATE(button, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(thumb, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(checkbox, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(radio, NS_NewButtonBoxFrame),
    SCROLLABLE_XUL_CREATE(titlebar, NS_NewTitleBarFrame),
    SCROLLABLE_XUL_CREATE(resizer, NS_NewResizerFrame),
    SCROLLABLE_XUL_CREATE(toolbarpaletteitem, NS_NewBoxFrame),
    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(menulist, 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),
#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, aStyle, sXULTagData,
                       ArrayLength(sXULTagData));
}

#ifdef MOZ_XUL
/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindPopupGroupData(const Element& aElement, ComputedStyle&)
{
  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(const Element& aElement, ComputedStyle&)
{
  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, ComputedStyle *aContext)
{
  // XXXbz do we really need to set up the block formatting context root? If the
  // parent is not a block we'll get it anyway, and if it is, do we want it?
  return NS_NewBlockFormattingContext(aPresShell, aContext);
}

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULDescriptionData(const Element& aElement,
                                              ComputedStyle&)
{
  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(const Element& aElement,
                                          ComputedStyle&)
{
  nsCOMPtr<nsIDocShell> treeItem = aElement.OwnerDoc()->GetDocShell();
  if (treeItem && nsIDocShellTreeItem::typeChrome == treeItem->ItemType()) {
    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 */

#endif /* MOZ_XUL */

/* static */
const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindXULDisplayData(const nsStyleDisplay& aDisplay,
                                          const Element& aElement)
{
  static const FrameConstructionDataByDisplay sXULDisplayData[] = {
    SCROLLABLE_ABSPOS_CONTAINER_XUL_DISPLAY_CREATE(StyleDisplay::MozBox,
                                                   NS_NewBoxFrame),
    SCROLLABLE_ABSPOS_CONTAINER_XUL_DISPLAY_CREATE(StyleDisplay::MozInlineBox,
                                                   NS_NewBoxFrame),
#ifdef MOZ_XUL
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozGrid, NS_NewGridBoxFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozInlineGrid, NS_NewGridBoxFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozGridGroup,
                                  NS_NewGridRowGroupFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozGridLine,
                                  NS_NewGridRowLeafFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozStack, NS_NewStackFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozInlineStack, NS_NewStackFrame),
    SIMPLE_XUL_DISPLAY_CREATE(StyleDisplay::MozDeck, NS_NewDeckFrame),
    SCROLLABLE_XUL_DISPLAY_CREATE(StyleDisplay::MozGroupbox, NS_NewGroupBoxFrame),
    FCDATA_FOR_DISPLAY(StyleDisplay::MozPopup,
      FCDATA_DECL(FCDATA_DISALLOW_OUT_OF_FLOW | FCDATA_IS_POPUP |
                  FCDATA_SKIP_ABSPOS_PUSH, NS_NewMenuPopupFrame))
#endif /* MOZ_XUL */
  };

  if (aDisplay.mDisplay < StyleDisplay::MozBox) {
    return nullptr;
  }

  MOZ_ASSERT(aDisplay.mDisplay <= StyleDisplay::MozPopup,
             "Someone added a new display value?");

  if (aDisplay.mDisplay == StyleDisplay::MozBox ||
      aDisplay.mDisplay == StyleDisplay::MozInlineBox) {
    if (!aElement.IsInNativeAnonymousSubtree() &&
        aElement.OwnerDoc()->IsContentDocument()) {
      aElement.OwnerDoc()->WarnOnceAbout(nsIDocument::eMozBoxOrInlineBoxDisplay);
    }

    // If we're emulating -moz-box with flexbox, then treat it as non-XUL and
    // return null (except for scrollcorners which have to be XUL becuase their
    // parent reflows them with BoxReflow() which means they have to get
    // actual-XUL frames).
    if (StaticPrefs::layout_css_emulate_moz_box_with_flex() &&
        !aElement.IsXULElement(nsGkAtoms::scrollcorner)) {
      return nullptr;
    }
  }

  const FrameConstructionDataByDisplay& data =
    sXULDisplayData[size_t(aDisplay.mDisplay) - size_t(StyleDisplay::MozBox)];
  MOZ_ASSERT(aDisplay.mDisplay == data.mDisplay,
             "Did someone mess with the order?");

  return &data.mData;
}

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

  nsFrameItems anonymousItems;

  RefPtr<ComputedStyle> 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 == StyleDisplay::MozStack ||
          displayStyle->mDisplay == StyleDisplay::MozInlineStack);
    } 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.
  //
  // We can't take the normal ProcessChildren path, because the NAC needs to
  // be parented to the scrollframe, and everything else needs to be parented
  // to the scrolledframe.
  AutoTArray<nsIAnonymousContentCreator::ContentInfo, 4> scrollNAC;
  DebugOnly<nsresult> rv = GetAnonymousContent(aContent, gfxScrollFrame, scrollNAC);
  MOZ_ASSERT(NS_SUCCEEDED(rv));
  if (scrollNAC.Length() > 0) {
    AutoFrameConstructionItemList items(this);
    AddFCItemsForAnonymousContent(aState, gfxScrollFrame, scrollNAC, items);
    ConstructFramesFromItemList(aState, items, gfxScrollFrame,
                                /* aParentIsWrapperAnonBox = */ false,
                                anonymousItems);
  }

  aNewFrame = gfxScrollFrame;
  gfxScrollFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

  // we used the style that was passed in. So resolve another one.
  ServoStyleSet* styleSet = mPresShell->StyleSet();
  RefPtr<ComputedStyle> scrolledChildStyle =
    styleSet->ResolveInheritingAnonymousBoxStyle(aScrolledPseudo, contentStyle);

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

  return scrolledChildStyle.forget();
}

void
nsCSSFrameConstructor::FinishBuildingScrollFrame(nsContainerFrame* 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 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)
 */
void
nsCSSFrameConstructor::BuildScrollFrame(nsFrameConstructorState& aState,
                                        nsIContent*              aContent,
                                        ComputedStyle*           aContentStyle,
                                        nsIFrame*                aScrolledFrame,
                                        nsContainerFrame*        aParentFrame,
                                        nsContainerFrame*&       aNewFrame)
{
  RefPtr<ComputedStyle> scrolledContentStyle =
    BeginBuildingScrollFrame(aState, aContent, aContentStyle, aParentFrame,
                             nsCSSAnonBoxes::scrolledContent(),
                             false, aNewFrame);

  aScrolledFrame->SetComputedStyleWithoutNotification(scrolledContentStyle);
  InitAndRestoreFrame(aState, aContent, aNewFrame, aScrolledFrame);

  FinishBuildingScrollFrame(aNewFrame, aScrolledFrame);
}

const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDisplayData(const nsStyleDisplay& aDisplay,
                                       const Element& aElement)
{
  static_assert(eParentTypeCount < (1 << (32 - FCDATA_PARENT_TYPE_OFFSET)),
                "Check eParentTypeCount should not overflow");

  // The style system ensures that floated and positioned frames are
  // block-level.
  NS_ASSERTION(!(aDisplay.IsFloatingStyle() ||
                 aDisplay.IsAbsolutelyPositionedStyle()) ||
               aDisplay.IsBlockOutsideStyle() ||
               aDisplay.mDisplay == StyleDisplay::Contents,
               "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.IsHTMLElement(nsGkAtoms::body)) {
    if (nsPresContext* presContext = mPresShell->GetPresContext()) {
      propagatedScrollToViewport =
        presContext->UpdateViewportScrollStylesOverride() == &aElement;
    }
  }

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

  if (aDisplay.IsBlockInsideStyle()) {
    // If the frame is a block-level frame and is scrollable, then wrap it in a
    // scroll frame.  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.
    // XXX Ignore tables for the time being (except caption)
    const uint32_t kCaptionCtorFlags =
      FCDATA_IS_TABLE_PART | FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable);
    bool caption = aDisplay.mDisplay == StyleDisplay::TableCaption;
    bool suppressScrollFrame = false;
    bool needScrollFrame = aDisplay.IsScrollableOverflow() &&
                           !propagatedScrollToViewport;
    if (needScrollFrame) {
      suppressScrollFrame = mPresShell->GetPresContext()->IsPaginated() &&
                            aDisplay.IsBlockOutsideStyle() &&
                            !aElement.IsInNativeAnonymousSubtree();
      if (!suppressScrollFrame) {
        static const FrameConstructionData sScrollableBlockData[2] =
          { FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructScrollableBlock),
            FULL_CTOR_FCDATA(kCaptionCtorFlags,
                             &nsCSSFrameConstructor::ConstructScrollableBlock) };
        return &sScrollableBlockData[caption];
      }

      // If the scrollable frame would have propagated its scrolling to the
      // viewport, we still want to construct a regular block rather than a
      // scrollframe so that it paginates correctly, but we don't want to set
      // the bit on the block that tells it to clip at paint time.
      if (mPresShell->GetPresContext()->
            ElementWouldPropagateScrollStyles(aElement)) {
        suppressScrollFrame = false;
      }
    }

    // Handle various non-scrollable blocks.
    static const FrameConstructionData sNonScrollableBlockData[2][2] = {
      { FULL_CTOR_FCDATA(0,
                         &nsCSSFrameConstructor::ConstructNonScrollableBlock),
        FULL_CTOR_FCDATA(kCaptionCtorFlags,
                         &nsCSSFrameConstructor::ConstructNonScrollableBlock) },
      { FULL_CTOR_FCDATA(FCDATA_FORCED_NON_SCROLLABLE_BLOCK,
                         &nsCSSFrameConstructor::ConstructNonScrollableBlock),
        FULL_CTOR_FCDATA(FCDATA_FORCED_NON_SCROLLABLE_BLOCK | kCaptionCtorFlags,
                         &nsCSSFrameConstructor::ConstructNonScrollableBlock) }
    };
    return &sNonScrollableBlockData[suppressScrollFrame][caption];
  }

  // If this is for a <body> node and we've propagated the scroll-frame to the
  // viewport, we need to make sure not to add another layer of scrollbars, so
  // we use a different FCData struct without FCDATA_MAY_NEED_SCROLLFRAME.
  if (propagatedScrollToViewport && aDisplay.IsScrollableOverflow()) {
    if (aDisplay.mDisplay == StyleDisplay::Flex ||
        aDisplay.mDisplay == StyleDisplay::WebkitBox ||
        (StaticPrefs::layout_css_emulate_moz_box_with_flex() &&
         aDisplay.mDisplay == StyleDisplay::MozBox)) {
      static const FrameConstructionData sNonScrollableFlexData =
        FCDATA_DECL(0, NS_NewFlexContainerFrame);
      return &sNonScrollableFlexData;
    }
    if (aDisplay.mDisplay == StyleDisplay::Grid) {
      static const FrameConstructionData sNonScrollableGridData =
        FCDATA_DECL(0, NS_NewGridContainerFrame);
      return &sNonScrollableGridData;
    }
  }

  // NOTE: Make sure to keep this up to date with the StyleDisplay definition!
  static const FrameConstructionDataByDisplay sDisplayData[] = {
    FCDATA_FOR_DISPLAY(StyleDisplay::None, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::Block, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::FlowRoot, UNREACHABLE_FCDATA()),
    // 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!
    FCDATA_FOR_DISPLAY(StyleDisplay::Inline,
      FULL_CTOR_FCDATA(FCDATA_IS_INLINE | FCDATA_IS_LINE_PARTICIPANT,
                       &nsCSSFrameConstructor::ConstructInline)),
    FCDATA_FOR_DISPLAY(StyleDisplay::InlineBlock, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::ListItem, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::Table,
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructTable)),
    FCDATA_FOR_DISPLAY(StyleDisplay::InlineTable,
      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 ComputedStyle::ApplyStyleFixups().
    FCDATA_FOR_DISPLAY(StyleDisplay::TableRowGroup,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                       &nsCSSFrameConstructor::ConstructTableRowOrRowGroup)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableColumn,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeColGroup),
                       &nsCSSFrameConstructor::ConstructTableCol)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableColumnGroup,
      FCDATA_DECL(FCDATA_IS_TABLE_PART | FCDATA_DISALLOW_OUT_OF_FLOW |
                  FCDATA_SKIP_ABSPOS_PUSH |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                  NS_NewTableColGroupFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableHeaderGroup,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                       &nsCSSFrameConstructor::ConstructTableRowOrRowGroup)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableFooterGroup,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeTable),
                       &nsCSSFrameConstructor::ConstructTableRowOrRowGroup)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableRow,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRowGroup),
                       &nsCSSFrameConstructor::ConstructTableRowOrRowGroup)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableCell,
      FULL_CTOR_FCDATA(FCDATA_IS_TABLE_PART |
                       FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRow),
                       &nsCSSFrameConstructor::ConstructTableCell)),
    FCDATA_FOR_DISPLAY(StyleDisplay::TableCaption, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::Flex,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::InlineFlex,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::Grid,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewGridContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::InlineGrid,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewGridContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::Ruby,
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT, NS_NewRubyFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::RubyBase,
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRubyBaseContainer),
                  NS_NewRubyBaseFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::RubyBaseContainer,
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRuby),
                  NS_NewRubyBaseContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::RubyText,
      FCDATA_DECL(FCDATA_IS_LINE_PARTICIPANT |
                  FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRubyTextContainer),
                  NS_NewRubyTextFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::RubyTextContainer,
      FCDATA_DECL(FCDATA_DESIRED_PARENT_TYPE_TO_BITS(eTypeRuby),
                  NS_NewRubyTextContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::Contents, UNREACHABLE_FCDATA()),
    FCDATA_FOR_DISPLAY(StyleDisplay::WebkitBox,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::WebkitInlineBox,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::MozBox,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
    FCDATA_FOR_DISPLAY(StyleDisplay::MozInlineBox,
      FCDATA_DECL(FCDATA_MAY_NEED_SCROLLFRAME, NS_NewFlexContainerFrame)),
  };
  static_assert(ArrayLength(sDisplayData) == size_t(StyleDisplay::MozInlineBox) + 1,
                "Be sure to update sDisplayData if you touch StyleDisplay");
  MOZ_ASSERT(StaticPrefs::layout_css_emulate_moz_box_with_flex() ||
             (aDisplay.mDisplay != StyleDisplay::MozBox &&
              aDisplay.mDisplay != StyleDisplay::MozInlineBox),
             "-moz-{inline-}box as XUL should have already been handled");
  MOZ_ASSERT(size_t(aDisplay.mDisplay) < ArrayLength(sDisplayData),
             "XUL display data should have already been handled");

  // See the mDisplay fixup code in StyleAdjuster::adjust.
  MOZ_ASSERT(aDisplay.mDisplay != StyleDisplay::Contents ||
             !aElement.IsRootOfNativeAnonymousSubtree(),
             "display:contents on anonymous content is unsupported");

  const FrameConstructionDataByDisplay& data =
    sDisplayData[size_t(aDisplay.mDisplay)];

  MOZ_ASSERT(data.mDisplay == aDisplay.mDisplay,
             "Someone messed up the order in the display values");

  return &data.mData;
}

nsIFrame*
nsCSSFrameConstructor::ConstructScrollableBlock(nsFrameConstructorState& aState,
                                                FrameConstructionItem&   aItem,
                                                nsContainerFrame*        aParentFrame,
                                                const nsStyleDisplay*    aDisplay,
                                                nsFrameItems&            aFrameItems)
{
  return ConstructScrollableBlockWithConstructor(aState, aItem, aParentFrame,
                                                 aDisplay, aFrameItems,
                                                 NS_NewBlockFormattingContext);
}

nsIFrame*
nsCSSFrameConstructor::ConstructScrollableBlockWithConstructor(
  nsFrameConstructorState& aState,
  FrameConstructionItem& aItem,
  nsContainerFrame* aParentFrame,
  const nsStyleDisplay* aDisplay,
  nsFrameItems& aFrameItems,
  BlockFrameCreationFunc aConstructor)
{
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  nsContainerFrame* newFrame = nullptr;
  RefPtr<ComputedStyle> scrolledContentStyle
    = BeginBuildingScrollFrame(aState, content, computedStyle,
                               aState.GetGeometricParent(*aDisplay, aParentFrame),
                               nsCSSAnonBoxes::scrolledContent(),
                               false, newFrame);

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

  // 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, aParentFrame);

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

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

  return newFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructNonScrollableBlock(nsFrameConstructorState& aState,
                                                   FrameConstructionItem&   aItem,
                                                   nsContainerFrame*        aParentFrame,
                                                   const nsStyleDisplay*    aDisplay,
                                                   nsFrameItems&            aFrameItems)
{
  return ConstructNonScrollableBlockWithConstructor(aState, aItem, aParentFrame,
                                                    aDisplay, aFrameItems,
                                                    NS_NewBlockFrame);
}

nsIFrame*
nsCSSFrameConstructor::ConstructNonScrollableBlockWithConstructor(
  nsFrameConstructorState& aState,
  FrameConstructionItem& aItem,
  nsContainerFrame* aParentFrame,
  const nsStyleDisplay* aDisplay,
  nsFrameItems& aFrameItems,
  BlockFrameCreationFunc aConstructor)
{
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  // 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;
  nsFrameState flags = nsFrameState(0);
  if ((aDisplay->IsAbsolutelyPositionedStyle() ||
       aDisplay->IsFloatingStyle() ||
       StyleDisplay::InlineBlock == aDisplay->mDisplay ||
       clipPaginatedOverflow) &&
      !nsSVGUtils::IsInSVGTextSubtree(aParentFrame)) {
    flags = NS_BLOCK_FORMATTING_CONTEXT_STATE_BITS;
    if (clipPaginatedOverflow) {
      flags |= NS_BLOCK_CLIP_PAGINATED_OVERFLOW;
    }
  }

  nsContainerFrame* newFrame = aConstructor(mPresShell, computedStyle);
  newFrame->AddStateBits(flags);
  ConstructBlock(aState, aItem.mContent,
                 aState.GetGeometricParent(*aDisplay, aParentFrame),
                 aParentFrame, computedStyle, &newFrame,
                 aFrameItems,
                 aDisplay->IsAbsPosContainingBlock(newFrame) ? newFrame : nullptr,
                 aItem.mPendingBinding);
  return newFrame;
}


void
nsCSSFrameConstructor::InitAndRestoreFrame(const nsFrameConstructorState& aState,
                                           nsIContent*              aContent,
                                           nsContainerFrame*        aParentFrame,
                                           nsIFrame*                aNewFrame,
                                           bool                     aAllowCounters)
{
  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<ComputedStyle>
nsCSSFrameConstructor::ResolveComputedStyle(nsIContent* aContent)
{
  ServoStyleSet* styleSet = mPresShell->StyleSet();

  if (auto* element = Element::FromNode(aContent)) {
    return styleSet->ResolveServoStyle(*element);
  }

  MOZ_ASSERT(aContent->IsText(),
             "shouldn't waste time creating ComputedStyles for "
             "comments and processing instructions");

  Element* parent = aContent->GetFlattenedTreeParentElement();
  MOZ_ASSERT(parent, "Text out of the flattened tree?");

  // FIXME(emilio): We can't use ResolveServoStyle properly because this text
  // node can come from non-lazy frame construction, in which case the style we
  // inherit from can indeed be out-of-date. After an eventual XBL removal, this
  // can go. Note that this is not a correctness issue, since we'll restyle
  // later in any case.
  //
  // Also, this probably doesn't need to be a strong ref...
  //
  // Do NOT add new callers to this function in this file, ever, or I'll find
  // out.
  RefPtr<ComputedStyle> parentStyle =
    Servo_Element_GetPrimaryComputedValues(parent).Consume();
  return styleSet->ResolveStyleForText(aContent, parentStyle);
}

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

  nsAtom* anonPseudo = nsCSSAnonBoxes::mozMathMLAnonymousBlock();

  ComputedStyle* parentContext =
    nsFrame::CorrectStyleParentFrame(aParentFrame,
                                     anonPseudo)->Style();
  ServoStyleSet* styleSet = mPresShell->StyleSet();
  RefPtr<ComputedStyle> blockContext;
  blockContext = styleSet->
    ResolveInheritingAnonymousBoxStyle(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.
  nsContainerFrame* blockFrame =
    NS_NewMathMLmathBlockFrame(mPresShell, blockContext);

  InitAndRestoreFrame(aState, aContent, aParentFrame, blockFrame);
  ReparentFrames(this, blockFrame, aBlockItems, false);
  // We have to walk over aBlockItems before we hand it over to blockFrame.
  for (nsIFrame* f : aBlockItems) {
    f->SetParentIsWrapperAnonBox();
  }
  // 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(const Element& aElement,
                                      ComputedStyle& aStyle)
{
  MOZ_ASSERT(aElement.IsMathMLElement());

  nsAtom* tag = aElement.NodeInfo()->NameAtom();

  // Handle <math> specially, because it sometimes produces inlines
  if (tag == nsGkAtoms::math) {
    // The IsBlockOutsideStyle() check must match what
    // specified::Display::equivalent_block_display is checking for
    // already-block-outside things. Though the behavior here for the
    // display:table case is pretty weird...
    if (aStyle.StyleDisplay()->IsBlockOutsideStyle()) {
      static const FrameConstructionData sBlockMathData =
        FCDATA_DECL(FCDATA_FORCE_NULL_ABSPOS_CONTAINER |
                    FCDATA_WRAP_KIDS_IN_BLOCKS,
                    NS_NewMathMLmathBlockFrame);
      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_NewMathMLmmultiscriptsFrame),
    SIMPLE_MATHML_CREATE(msub_, NS_NewMathMLmmultiscriptsFrame),
    SIMPLE_MATHML_CREATE(msubsup_, NS_NewMathMLmmultiscriptsFrame),
    SIMPLE_MATHML_CREATE(munder_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(mover_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(munderover_, NS_NewMathMLmunderoverFrame),
    SIMPLE_MATHML_CREATE(mphantom_, NS_NewMathMLmrowFrame),
    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_NewMathMLmrowFrame),
    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(tag, aElement, aStyle, sMathMLData,
                       ArrayLength(sMathMLData));
}


nsContainerFrame*
nsCSSFrameConstructor::ConstructFrameWithAnonymousChild(
                                   nsFrameConstructorState& aState,
                                   FrameConstructionItem&   aItem,
                                   nsContainerFrame*        aParentFrame,
                                   nsFrameItems&            aFrameItems,
                                   ContainerFrameCreationFunc aConstructor,
                                   ContainerFrameCreationFunc aInnerConstructor,
                                   nsCSSAnonBoxPseudoStaticAtom* aInnerPseudo,
                                   bool                     aCandidateRootFrame)
{
  nsIContent* const content = aItem.mContent;
  ComputedStyle* const computedStyle = aItem.mComputedStyle;

  // Create the outer frame:
  nsContainerFrame* newFrame = aConstructor(mPresShell, computedStyle);

  InitAndRestoreFrame(aState, content,
                      aCandidateRootFrame ?
                        aState.GetGeometricParent(*computedStyle->StyleDisplay(),
                                                  aParentFrame) :
                        aParentFrame,
                      newFrame);
  newFrame->AddStateBits(NS_FRAME_OWNS_ANON_BOXES);

  // Create the pseudo SC for the anonymous wrapper child as a child of the SC:
  RefPtr<ComputedStyle> scForAnon;
  scForAnon = mPresShell->StyleSet()->
    ResolveInheritingAnonymousBoxStyle(aInnerPseudo, computedStyle);

  // Create the anonymous inner wrapper frame
  nsContainerFrame* innerFrame = aInnerConstructor(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, aParentFrame,
                  aCandidateRootFrame, aCandidateRootFrame);

  if (!mRootElementFrame && aCandidateRootFrame) {
    // 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,
                                aItem.mFCData->mBits & FCDATA_IS_WRAPPER_ANON_BOX,
                                childItems);
  } else {
    ProcessChildren(aState, content, computedStyle, innerFrame,
                    true, childItems, false, aItem.mPendingBinding);
  }

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

  return newFrame;
}

nsIFrame*
nsCSSFrameConstructor::ConstructOuterSVG(nsFrameConstructorState& aState,
                                         FrameConstructionItem&   aItem,
                                         nsContainerFrame*        aParentFrame,
                                         const nsStyleDisplay*    aDisplay,
                                         nsFrameItems&            aFrameItems)
{
  return ConstructFrameWithAnonymousChild(
      aState, aItem, aParentFrame, aFrameItems,
      NS_NewSVGOuterSVGFrame, NS_NewSVGOuterSVGAnonChildFrame,
      nsCSSAnonBoxes::mozSVGOuterSVGAnonChild(), true);
}

nsIFrame*
nsCSSFrameConstructor::ConstructMarker(nsFrameConstructorState& aState,
                                       FrameConstructionItem&   aItem,
                                       nsContainerFrame*        aParentFrame,
                                       const nsStyleDisplay*    aDisplay,
                                       nsFrameItems&            aFrameItems)
{
  return ConstructFrameWithAnonymousChild(
      aState, aItem, aParentFrame, aFrameItems,
      NS_NewSVGMarkerFrame, NS_NewSVGMarkerAnonChildFrame,
      nsCSSAnonBoxes::mozSVGMarkerAnonChild(), false);
}

// 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 nsAtom* 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(const Element& aElement,
                                   nsIFrame* aParentFrame,
                                   bool aIsWithinSVGText,
                                   bool aAllowsTextPathChild,
                                   ComputedStyle& aStyle)
{
  MOZ_ASSERT(aElement.IsSVGElement());

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

  bool parentIsSVG = aIsWithinSVGText;
  nsIContent* parentContent =
    aParentFrame ? aParentFrame->GetContent() : nullptr;

  nsAtom* tag = aElement.NodeInfo()->NameAtom();

  // XXXbz should this really be based on the 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) {
    // 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 =
      parentContent->IsSVGElement() &&
      parentContent->NodeInfo()->NameAtom() != nsGkAtoms::foreignObject;
  }

  if ((tag != nsGkAtoms::svg && !parentIsSVG) ||
      (tag == nsGkAtoms::desc || tag == nsGkAtoms::title ||
       tag == nsGkAtoms::metadata)) {
    // 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/metadata
    return &sSuppressData;
  }

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

  if (tag == 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;
  }

  if (tag == nsGkAtoms::marker) {
    static const FrameConstructionData sMarkerSVGData =
      FULL_CTOR_FCDATA(0, &nsCSSFrameConstructor::ConstructMarker);
    return &sMarkerSVGData;
  }

  nsCOMPtr<SVGTests> tests =
    do_QueryInterface(const_cast<Element*>(&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.
    if (aIsWithinSVGText) {
      // SVGTextFrame doesn't handle conditional processing attributes,
      // so don't create frames for descendants of <text> with failing
      // attributes.  We need frames not to be created so that text layout
      // is correct.
      return &sSuppressData;
    }
    // If we're not inside <text>, create an nsSVGContainerFrame (which is a
    // frame that doesn't render) so that paint servers can still be referenced,
    // even if they live inside an element with failing conditional processing
    // attributes.
    return &sContainerData;
  }

  // Ensure that a stop frame is a child of a gradient and that gradients
  // can only have stop children.
  bool parentIsGradient =
    aParentFrame && (aParentFrame->IsSVGLinearGradientFrame() ||
                     aParentFrame->IsSVGRadialGradientFrame());
  bool stop = (tag == nsGkAtoms::stop);
  if ((parentIsGradient && !stop) || (!parentIsGradient && stop)) {
    return &sSuppressData;
  }

  // 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->IsSVGFilterFrame();
  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->IsSVGFEContainerFrame();
  if ((parentIsFEContainerFrame && !IsFilterPrimitiveChildTag(tag)) ||
      (!parentIsFEContainerFrame && IsFilterPrimitiveChildTag(tag))) {
    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 (tag == nsGkAtoms::textPath) {
      if (aAllowsTextPathChild) {
        return &sTSpanData;
      }
    } else if (tag == nsGkAtoms::tspan ||
               tag == nsGkAtoms::a) {
      return &sTSpanData;
    }
    return &sSuppressData;
  } else if (tag == nsGkAtoms::tspan ||
             tag == nsGkAtoms::textPath) {
    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(symbol, NS_NewSVGSymbolFrame),
    SIMPLE_SVG_CREATE(polygon, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(polyline, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(circle, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(ellipse, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(line, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(rect, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(path, NS_NewSVGGeometryFrame),
    SIMPLE_SVG_CREATE(defs, NS_NewSVGContainerFrame),
    SIMPLE_SVG_CREATE(generic_, NS_NewSVGGenericContainerFrame),
    { nsGkAtoms::text,
      FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW |
                                 FCDATA_ALLOW_BLOCK_STYLES,
                                 NS_NewSVGTextFrame,
                                 nsCSSAnonBoxes::mozSVGText()) },
    { nsGkAtoms::foreignObject,
      FCDATA_WITH_WRAPPING_BLOCK(FCDATA_DISALLOW_OUT_OF_FLOW,
                                 NS_NewSVGForeignObjectFrame,
                                 nsCSSAnonBoxes::mozSVGForeignContent()) },
    SIMPLE_SVG_CREATE(a, NS_NewSVGAFrame),
    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(image, NS_NewSVGImageFrame),
    SIMPLE_SVG_CREATE(clipPath, NS_NewSVGClipPathFrame),
    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(feDropShadow, 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(tag, aElement, aStyle, sSVGData, ArrayLength(sSVGData));

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

  return data;
}

void
nsCSSFrameConstructor::AddPageBreakItem(nsIContent* aContent,
                                        FrameConstructionItemList& aItems)
{
  RefPtr<ComputedStyle> pseudoStyle =
    mPresShell->StyleSet()->
      ResolveNonInheritingAnonymousBoxStyle(nsCSSAnonBoxes::pageBreak());

  MOZ_ASSERT(pseudoStyle->StyleDisplay()->mDisplay == StyleDisplay::Block,
             "Unexpected display");

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

  aItems.AppendItem(this, &sPageBreakData, aContent, nullptr,
                    pseudoStyle.forget(), true);
}

bool
nsCSSFrameConstructor::ShouldCreateItemsForChild(nsFrameConstructorState& aState,
                                                 nsIContent* aContent,
                                                 nsContainerFrame* aParentFrame)
{
  aContent->UnsetFlags(NODE_DESCENDANTS_NEED_FRAMES | NODE_NEEDS_FRAME);
  // 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) {
    MOZ_ASSERT(false,
               "asked to create frame construction item for a node that "
               "already has a frame");
    return false;
  }

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

  // never create frames for comments or PIs
  if (aContent->IsComment() || aContent->IsProcessingInstruction()) {
    return false;
  }

  return true;
}

void
nsCSSFrameConstructor::DoAddFrameConstructionItems(nsFrameConstructorState& aState,
                                                   nsIContent* aContent,
                                                   ComputedStyle* aComputedStyle,
                                                   bool aSuppressWhiteSpaceOptimizations,
                                                   nsContainerFrame* aParentFrame,
                                                   FrameConstructionItemList& aItems)
{
  uint32_t flags = ITEM_ALLOW_XBL_BASE | ITEM_ALLOW_PAGE_BREAK;
  if (aParentFrame) {
    if (nsSVGUtils::IsInSVGTextSubtree(aParentFrame)) {
      flags |= ITEM_IS_WITHIN_SVG_TEXT;
    }
    if (aParentFrame->IsBlockFrame() && aParentFrame->GetParent() &&
        aParentFrame->GetParent()->IsSVGTextFrame()) {
      flags |= ITEM_ALLOWS_TEXT_PATH_CHILD;
    }
  }
  AddFrameConstructionItemsInternal(aState, aContent, aParentFrame,
                                    aSuppressWhiteSpaceOptimizations,
                                    aComputedStyle,
                                    flags, aItems);
}

void
nsCSSFrameConstructor::AddFrameConstructionItems(nsFrameConstructorState& aState,
                                                 nsIContent* aContent,
                                                 bool aSuppressWhiteSpaceOptimizations,
                                                 const InsertionPoint& aInsertion,
                                                 FrameConstructionItemList& aItems)
{
  nsContainerFrame* parentFrame = aInsertion.mParentFrame;
  if (!ShouldCreateItemsForChild(aState, aContent, parentFrame)) {
    return;
  }
  RefPtr<ComputedStyle> computedStyle = ResolveComputedStyle(aContent);
  DoAddFrameConstructionItems(aState, aContent, computedStyle,
                              aSuppressWhiteSpaceOptimizations, parentFrame,
                              aItems);
}

// Whether we should suppress frames for a child under a <select> frame.
//
// 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.
static bool
ShouldSuppressFrameInSelect(const nsIContent* aParent,
                            const nsIContent& aChild)
{
  if (!aParent ||
      !aParent->IsAnyOfHTMLElements(nsGkAtoms::select, nsGkAtoms::optgroup)) {
    return false;
  }

  // If we're in any display: contents subtree, just suppress the frame.
  //
  // We can't be regular NAC, since display: contents has no frame to generate
  // them off.
  if (aChild.GetParent() != aParent) {
    return true;
  }

  // Option is always fine.
  if (aChild.IsHTMLElement(nsGkAtoms::option)) {
    return false;
  }

  // <optgroup> is OK in <select> but not in <optgroup>.
  if (aChild.IsHTMLElement(nsGkAtoms::optgroup) &&
      aParent->IsHTMLElement(nsGkAtoms::select)) {
    return false;
  }

  // Allow native anonymous content no matter what.
  if (aChild.IsRootOfAnonymousSubtree()) {
    return false;
  }

  return true;
}

static bool
ShouldSuppressFrameInNonOpenDetails(const HTMLDetailsElement* aDetails,
                                    const nsIContent& aChild)
{
  if (!aDetails || aDetails->Open()) {
    return false;
  }

  if (aChild.GetParent() != aDetails) {
    return true;
  }

  auto* summary = HTMLSummaryElement::FromNode(aChild);
  if (summary && summary->IsMainSummary()) {
    return false;
  }

  // Don't suppress NAC, unless it's ::before or ::after.
  if (aChild.IsRootOfAnonymousSubtree() &&
      !aChild.IsGeneratedContentContainerForBefore() &&
      !aChild.IsGeneratedContentContainerForAfter()) {
    return false;
  }

  return true;
}

const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindDataForContent(nsIContent& aContent,
                                          ComputedStyle& aStyle,
                                          nsIFrame* aParentFrame,
                                          nsAtom* aTag,
                                          uint32_t aFlags)
{
  MOZ_ASSERT(aStyle.StyleDisplay()->mDisplay != StyleDisplay::None &&
             aStyle.StyleDisplay()->mDisplay != StyleDisplay::Contents,
             "These two special display values should be handled earlier");

  if (auto* text = Text::FromNode(aContent)) {
    return FindTextData(*text, aParentFrame);
  }

  return FindElementData(*aContent.AsElement(),
                         aStyle,
                         aParentFrame,
                         aTag,
                         aFlags);
}

const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindElementData(const Element& aElement,
                                       ComputedStyle& aStyle,
                                       nsIFrame* aParentFrame,
                                       nsAtom* aTag,
                                       uint32_t aFlags)
{
  // Don't create frames for non-SVG element children of SVG elements.
  if (!aElement.IsSVGElement()) {
    if (aParentFrame && IsFrameForSVG(aParentFrame) &&
        !aParentFrame->IsFrameOfType(nsIFrame::eSVGForeignObject)) {
      return nullptr;
    }
    if (aFlags & ITEM_IS_WITHIN_SVG_TEXT) {
      return nullptr;
    }
  }

  if (auto* data = FindElementTagData(aElement, aStyle, aParentFrame, aTag, aFlags)) {
    return data;
  }

  // Check for 'content: <image-url>' on the element (which makes us ignore
  // 'display' values other than 'none' or 'contents').
  if (ShouldCreateImageFrameForContent(aElement, aStyle)) {
    static const FrameConstructionData sImgData =
      SIMPLE_FCDATA(NS_NewImageFrameForContentProperty);
    return &sImgData;
  }

  const auto& display = *aStyle.StyleDisplay();
  if (auto* data = FindXULDisplayData(display, aElement)) {
    return data;
  }

  return FindDisplayData(display, aElement);
}

const nsCSSFrameConstructor::FrameConstructionData*
nsCSSFrameConstructor::FindElementTagData(const Element& aElement,
                                          ComputedStyle& aStyle,
                                          nsIFrame* aParentFrame,
                                          nsAtom* aTag,
                                          uint32_t aFlags)
{
  switch (aElement.GetNameSpaceID()) {
    case kNameSpaceID_XHTML:
      return FindHTMLData(aElement, aParentFrame, aStyle);
    case kNameSpaceID_MathML:
      return FindMathMLData(aElement, aStyle);
    case kNameSpaceID_SVG:
      return FindSVGData(aElement,
                         aParentFrame,
                         aFlags & ITEM_IS_WITHIN_SVG_TEXT,
                         aFlags & ITEM_ALLOWS_TEXT_PATH_CHILD,
                         aStyle);
    case kNameSpaceID_XUL:
      return FindXULTagData(aElement, aTag, aStyle);
    default:
      return nullptr;
  }
}

nsCSSFrameConstructor::XBLBindingLoadInfo::XBLBindingLoadInfo(
  already_AddRefed<ComputedStyle>&& aStyle,
  mozilla::UniquePtr<PendingBinding> aPendingBinding,
  nsAtom* aTag)
  : mStyle(std::move(aStyle))
  , mPendingBinding(std::move(aPendingBinding))
  , mTag(aTag)
{
  MOZ_ASSERT(mTag);
  MOZ_ASSERT(mStyle);
}

nsCSSFrameConstructor::XBLBindingLoadInfo::XBLBindingLoadInfo(nsIContent& aContent,
                                                              ComputedStyle& aStyle)
  : mStyle(&aStyle)
  , mPendingBinding(nullptr)
  , mTag(aContent.NodeInfo()->NameAtom())
{
}

nsCSSFrameConstructor::XBLBindingLoadInfo::XBLBindingLoadInfo() = default;

nsCSSFrameConstructor::XBLBindingLoadInfo
nsCSSFrameConstructor::LoadXBLBindingIfNeeded(nsIContent& aContent,
                                              ComputedStyle& aStyle,
                                              uint32_t aFlags)
{
  if (!(aFlags & ITEM_ALLOW_XBL_BASE)) {
    return { aContent, aStyle };
  }
  css::URLValue* binding = aStyle.StyleDisplay()->mBinding;
  if (!binding) {
    return { aContent, aStyle };
  }

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

  auto newPendingBinding = MakeUnique<PendingBinding>();

  bool resolveStyle;
  nsresult rv = xblService->LoadBindings(aContent.AsElement(),
                                         binding->GetURI(),
                                         binding->ExtraData()->Principal(),
                                         getter_AddRefs(newPendingBinding->mBinding),
                                         &resolveStyle);
  if (NS_FAILED(rv)) {
    if (rv == NS_ERROR_XBL_BLOCKED) {
      return { aContent, aStyle };
    }
    return { };
  }

  RefPtr<ComputedStyle> style = resolveStyle
    ? mPresShell->StyleSet()->ResolveServoStyle(*aContent.AsElement())
    : do_AddRef(&aStyle);

  nsAtom* tag = aContent.NodeInfo()->NameAtom();
  if (aContent.IsXULElement()) {
    int32_t overridenNamespace;
    nsAtom* overridenTag =
      mDocument->BindingManager()->ResolveTag(&aContent, &overridenNamespace);
    // Only allow overriding from & to XUL.
    if (overridenNamespace == kNameSpaceID_XUL) {
      tag = overridenTag;
    }
  }

  return { style.forget(), std::move(newPendingBinding), tag };
}


void
nsCSSFrameConstructor::AddFrameConstructionItemsInternal(nsFrameConstructorState& aState,
                                                         nsIContent* aContent,
                                                         nsContainerFrame* aParentFrame,
                                                         bool aSuppressWhiteSpaceOptimizations,
                                                         ComputedStyle* aComputedStyle,
                                                         uint32_t aFlags,
                                                         FrameConstructionItemList& aItems)
{
  MOZ_ASSERT(aContent->IsText() || aContent->IsElement(),
             "Shouldn't get anything else here!");
  MOZ_ASSERT(aContent->IsInComposedDoc());
  MOZ_ASSERT(!aContent->GetPrimaryFrame() || aState.mCreatingExtraFrames ||
             aContent->NodeInfo()->NameAtom() == nsGkAtoms::area);

  PendingBinding* pendingBinding = nullptr;
  RefPtr<ComputedStyle> style;
  nsAtom* tag;
  {
    XBLBindingLoadInfo xblInfo =
      LoadXBLBindingIfNeeded(*aContent, *aComputedStyle, aFlags);
    if (!xblInfo.mTag) {
      return;
    }

    if (xblInfo.mPendingBinding && xblInfo.mPendingBinding->mBinding) {
      pendingBinding = xblInfo.mPendingBinding.get();
      aState.AddPendingBinding(std::move(xblInfo.mPendingBinding));
    }

    style = xblInfo.mStyle.forget();
    aComputedStyle = style.get();

    tag = xblInfo.mTag;
  }

  const bool isGeneratedContent = !!(aFlags & ITEM_IS_GENERATED_CONTENT);
  MOZ_ASSERT(!isGeneratedContent || style->GetPseudo(),
             "Generated content should be a pseudo-element");

  FrameConstructionItem* item = nullptr;
  auto cleanupGeneratedContent = mozilla::MakeScopeExit([&]() {
    if (isGeneratedContent && !item) {
      MOZ_ASSERT(!IsDisplayContents(aContent),
                 "This would need to change if we support display: contents "
                 "in generated content");
      aContent->UnbindFromTree();
    }
  });

  const nsStyleDisplay& display = *style->StyleDisplay();

  // Pre-check for display "none" - if we find that, don't create
  // any frame at all
  if (display.mDisplay == StyleDisplay::None) {
    return;
  }

  if (display.mDisplay == StyleDisplay::Contents) {
    CreateGeneratedContentItem(aState, aParentFrame, *aContent->AsElement(),
                               *style, CSSPseudoElementType::before, aItems);

    FlattenedChildIterator iter(aContent);
    InsertionPoint insertion(aParentFrame, aContent);
    for (nsIContent* child = iter.GetNextChild(); child; child = iter.GetNextChild()) {
      AddFrameConstructionItems(aState,
                                child,
                                aSuppressWhiteSpaceOptimizations,
                                insertion,
                                aItems);
    }
    aItems.SetParentHasNoXBLChildren(!iter.XBLInvolved());

    CreateGeneratedContentItem(aState, aParentFrame, *aContent->AsElement(),
                               *style, CSSPseudoElementType::after, aItems);
    return;
  }


  nsIContent* parent = aParentFrame ? aParentFrame->GetContent() : nullptr;
  if (ShouldSuppressFrameInSelect(parent, *aContent)) {
    return;
  }

  // When constructing a child of a non-open <details>, create only the frame
  // for the main <summary> element, and skip other elements.  This only applies
  // to things that are not roots of native anonymous subtrees (except for
  // ::before and ::after); we always want to create "internal" anonymous
  // content.
  auto* details = HTMLDetailsElement::FromNodeOrNull(parent);
  if (ShouldSuppressFrameInNonOpenDetails(details, *aContent)) {
    return;
  }

  const FrameConstructionData* data =
    FindDataForContent(*aContent, *style, aParentFrame, tag, aFlags);
  if (!data || data->mBits & FCDATA_SUPPRESS_FRAME) {
    return;
  }

  bool isPopup = false;

#ifdef MOZ_XUL
  if ((data->mBits & FCDATA_IS_POPUP) &&
      (!aParentFrame || // Parent is inline
       !aParentFrame->IsMenuFrame())) {
    if (!aState.mPopupItems.containingBlock &&
        !aState.mHavePendingPopupgroup) {
      return;
    }

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

  uint32_t bits = data->mBits;

  // Inside colgroups, suppress everything except columns.
  if (aParentFrame && aParentFrame->IsTableColGroupFrame() &&
      (!(bits & FCDATA_IS_TABLE_PART) ||
       display.mDisplay != StyleDisplay::TableColumn)) {
    return;
  }

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

  if (canHavePageBreak && display.mBreakBefore) {
    AddPageBreakItem(aContent, aItems);
  }

  if (details && details->Open()) {
    auto* summary = HTMLSummaryElement::FromNode(aContent);
    if (summary && summary->IsMainSummary()) {
      // If details is open, the main summary needs to be rendered as if it is
      // the first child, so add the item to the front of the item list.
      item = aItems.PrependItem(this, data, aContent, pendingBinding,
                                style.forget(),
                                aSuppressWhiteSpaceOptimizations);
    }
  }

  if (!item) {
    item = aItems.AppendItem(this, data, aContent, pendingBinding,
                             style.forget(),
                             aSuppressWhiteSpaceOptimizations);
  }
  item->mIsText = !aContent->IsElement();
  item->mIsGeneratedContent = isGeneratedContent;
  item->mIsAnonymousContentCreatorContent =
    aFlags & ITEM_IS_ANONYMOUSCONTENTCREATOR_CONTENT;
  if (isGeneratedContent) {
    // We need to keep this alive until the frame takes ownership.
    // This corresponds to the Release in ConstructFramesFromItem.
    item->mContent->AddRef();
  }
  item->mIsRootPopupgroup =
    aContent->IsRootOfNativeAnonymousSubtree() &&
    aContent->IsXULElement() &&
    tag == nsGkAtoms::popupgroup;
  if (item->mIsRootPopupgroup) {
    aState.mHavePendingPopupgroup = true;
  }
  item->mIsPopup = isPopup;

  if (canHavePageBreak && display.mBreakAfter) {
    AddPageBreakItem(aContent, 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->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 == StyleDisplay::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 = 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.
      (!(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();
  }
}

/**
 * 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,
                                               nsContainerFrame* aParentFrame,
                                               nsFrameItems& aFrameItems)
{
  nsContainerFrame* adjParentFrame = aParentFrame;
  FrameConstructionItem& item = aIter.item();
  ComputedStyle* computedStyle = item.mComputedStyle;
  AdjustParentFrame(&adjParentFrame, item.mFCData, computedStyle);

  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) &&
        !computedStyle->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) &&
        !mAlwaysCreateFramesForIgnorableWhitespace &&
        item.IsWhitespace(aState))
      return;

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

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

  AutoRestore<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;
  }

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

  if (item.mIsGeneratedContent) {
    // This corresponds to the AddRef in AddFrameConstructionItemsInternal.
    // The frame owns the generated content now.
    item.mContent->Release();

    // 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;
  }
}


inline bool
IsRootBoxFrame(nsIFrame *aFrame)
{
  return (aFrame->IsRootFrame());
}

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

nsContainerFrame*
nsCSSFrameConstructor::GetAbsoluteContainingBlock(nsIFrame* aFrame,
                                                  ContainingBlockType aType)
{
  // 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;
    }

    // Look for the ICB.
    if (aType == FIXED_POS) {
      LayoutFrameType t = frame->Type();
      if (t == LayoutFrameType::Viewport || t == LayoutFrameType::PageContent) {
        return static_cast<nsContainerFrame*>(frame);
      }
    }

    // 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->IsAbsPosContainingBlock() ||
        (aType == FIXED_POS &&
         !frame->IsFixedPosContainingBlock())) {
      continue;
    }
    nsIFrame* absPosCBCandidate = frame;
    LayoutFrameType type = absPosCBCandidate->Type();
    if (type == LayoutFrameType::FieldSet) {
      absPosCBCandidate = static_cast<nsFieldSetFrame*>(absPosCBCandidate)->GetInner();
      if (!absPosCBCandidate) {
        continue;
      }
      type = absPosCBCandidate->Type();
    }
    if (type == LayoutFrameType::Scroll) {
      nsIScrollableFrame* scrollFrame = do_QueryFrame(absPosCBCandidate);
      absPosCBCandidate = scrollFrame->GetScrolledFrame();
      if (!absPosCBCandidate) {
        continue;
      }
      type = absPosCBCandidate->Type();
    }
    // Only first continuations can be containing blocks.
    absPosCBCandidate = absPosCBCandidate->FirstContinuation();
    // Is the frame really an absolute container?
    if (!absPosCBCandidate->IsAbsoluteContainer()) {
      continue;
    }

    // For tables, skip the inner frame and consider the table wrapper frame.
    if (type == LayoutFrameType::Table) {
      continue;
    }
    // For table wrapper frames, we can just return absPosCBCandidate.
    MOZ_ASSERT((nsContainerFrame*)do_QueryFrame(absPosCBCandidate),
               "abs.pos. containing block must be nsContainerFrame sub-class");
    return static_cast<nsContainerFrame*>(absPosCBCandidate);
  }

  MOZ_ASSERT(aType != FIXED_POS, "no ICB in this frame tree?");

  // 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.
  return mHasRootAbsPosContainingBlock ? mDocElementContainingBlock : nullptr;
}

nsContainerFrame*
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()) {
      MOZ_ASSERT((nsContainerFrame*)do_QueryFrame(containingBlock),
                 "float containing block must be nsContainerFrame sub-class");
      return static_cast<nsContainerFrame*>(containingBlock);
    }
  }

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

/**
 * This function will get the previous sibling to use for an append operation.
 *
 * It takes a parent frame (must not be null) and the next insertion sibling, if
 * the parent content is display: contents or has ::after content (may be null).
 */
static nsIFrame*
FindAppendPrevSibling(nsIFrame* aParentFrame, nsIFrame* aNextSibling)
{