layout/generic/nsFrame.cpp
author Daniel Holbert <dholbert@cs.stanford.edu>
Thu, 11 Apr 2013 07:51:58 -0700
changeset 128450 b16ed870d536c54d712865bd5676c180ca4b4e13
parent 128142 9cb8ac3f27a2a297248314c46e4d26c7f944c367
child 128543 8b5bc945e72f799492685699b3aa53d2a450431b
permissions -rw-r--r--
Bug 851379, part 4: Fix InitOffsets logging code to display horizontal and vertical percent basis, instead of just a containing block width. r=mats

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

/* base class of all rendering objects */

#include "mozilla/Attributes.h"
#include "mozilla/DebugOnly.h"

#include "nsCOMPtr.h"
#include "nsFrame.h"
#include "nsFrameList.h"
#include "nsPlaceholderFrame.h"
#include "nsLineLayout.h"
#include "nsIContent.h"
#include "nsContentUtils.h"
#include "nsIAtom.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsStyleContext.h"
#include "nsTableOuterFrame.h"
#include "nsView.h"
#include "nsViewManager.h"
#include "nsIScrollableFrame.h"
#include "nsPresContext.h"
#include "nsCRT.h"
#include "nsGUIEvent.h"
#include "nsIDOMEvent.h"
#include "nsAsyncDOMEvent.h"
#include "nsStyleConsts.h"
#include "nsIPresShell.h"
#include "prlog.h"
#include "prprf.h"
#include <stdarg.h>
#include "nsFrameManager.h"
#include "nsCSSRendering.h"
#include "nsLayoutUtils.h"

#include "nsIDOMNode.h"
#include "nsEventStateManager.h"
#include "nsISelection.h"
#include "nsISelectionPrivate.h"
#include "nsFrameSelection.h"
#include "nsHTMLParts.h"
#include "nsGkAtoms.h"
#include "nsCSSAnonBoxes.h"
#include "nsCSSPseudoElements.h"
#include "nsCSSFrameConstructor.h"

#include "nsFrameTraversal.h"
#include "nsStyleChangeList.h"
#include "nsIDOMRange.h"
#include "nsRange.h"
#include "nsITableCellLayout.h"//  "
#include "nsITextControlFrame.h"
#include "nsINameSpaceManager.h"
#include "nsIPercentHeightObserver.h"
#include "nsStyleStructInlines.h"
#include <algorithm>

#ifdef IBMBIDI
#include "nsBidiPresUtils.h"
#endif

// For triple-click pref
#include "nsIServiceManager.h"
#include "imgIContainer.h"
#include "imgIRequest.h"
#include "nsLayoutCID.h"
#include "nsUnicharUtils.h"
#include "nsError.h"
#include "nsContainerFrame.h"
#include "nsBoxLayoutState.h"
#include "nsBlockFrame.h"
#include "nsDisplayList.h"
#include "nsIObjectLoadingContent.h"
#include "nsExpirationTracker.h"
#include "nsSVGIntegrationUtils.h"
#include "nsSVGEffects.h"
#include "nsChangeHint.h"
#include "nsDeckFrame.h"
#include "nsTableFrame.h"
#include "nsSubDocumentFrame.h"

#include "gfxContext.h"
#include "nsRenderingContext.h"
#include "CSSCalc.h"
#include "nsAbsoluteContainingBlock.h"
#include "nsFontInflationData.h"
#include "nsAnimationManager.h"
#include "nsTransitionManager.h"

#include "mozilla/Preferences.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/css/ImageLoader.h"
#include "mozilla/gfx/Tools.h"

using namespace mozilla;
using namespace mozilla::layers;
using namespace mozilla::layout;
using namespace mozilla::css;

// Struct containing cached metrics for box-wrapped frames.
struct nsBoxLayoutMetrics
{
  nsSize mPrefSize;
  nsSize mMinSize;
  nsSize mMaxSize;

  nsSize mBlockMinSize;
  nsSize mBlockPrefSize;
  nscoord mBlockAscent;

  nscoord mFlex;
  nscoord mAscent;

  nsSize mLastSize;
};

struct nsContentAndOffset
{
  nsIContent* mContent;
  int32_t mOffset;
};

// Some Misc #defines
#define SELECTION_DEBUG        0
#define FORCE_SELECTION_UPDATE 1
#define CALC_DEBUG             0


#include "nsILineIterator.h"

//non Hack prototypes
#if 0
static void RefreshContentFrames(nsPresContext* aPresContext, nsIContent * aStartContent, nsIContent * aEndContent);
#endif

#include "prenv.h"

// Formerly the nsIFrameDebug interface

#ifdef DEBUG
static bool gShowFrameBorders = false;

void nsFrame::ShowFrameBorders(bool aEnable)
{
  gShowFrameBorders = aEnable;
}

bool nsFrame::GetShowFrameBorders()
{
  return gShowFrameBorders;
}

static bool gShowEventTargetFrameBorder = false;

void nsFrame::ShowEventTargetFrameBorder(bool aEnable)
{
  gShowEventTargetFrameBorder = aEnable;
}

bool nsFrame::GetShowEventTargetFrameBorder()
{
  return gShowEventTargetFrameBorder;
}

/**
 * Note: the log module is created during library initialization which
 * means that you cannot perform logging before then.
 */
static PRLogModuleInfo* gLogModule;

static PRLogModuleInfo* gStyleVerifyTreeLogModuleInfo;

static uint32_t gStyleVerifyTreeEnable = 0x55;

bool
nsFrame::GetVerifyStyleTreeEnable()
{
  if (gStyleVerifyTreeEnable == 0x55) {
    if (nullptr == gStyleVerifyTreeLogModuleInfo) {
      gStyleVerifyTreeLogModuleInfo = PR_NewLogModule("styleverifytree");
      gStyleVerifyTreeEnable = 0 != gStyleVerifyTreeLogModuleInfo->level;
    }
  }
  return gStyleVerifyTreeEnable;
}

void
nsFrame::SetVerifyStyleTreeEnable(bool aEnabled)
{
  gStyleVerifyTreeEnable = aEnabled;
}

PRLogModuleInfo*
nsFrame::GetLogModuleInfo()
{
  if (nullptr == gLogModule) {
    gLogModule = PR_NewLogModule("frame");
  }
  return gLogModule;
}

void
nsFrame::DumpFrameTree(nsIFrame* aFrame)
{
    RootFrameList(aFrame->PresContext(), stdout, 0);
}

void
nsFrame::RootFrameList(nsPresContext* aPresContext, FILE* out, int32_t aIndent)
{
  if (!aPresContext || !out)
    return;

  nsIPresShell *shell = aPresContext->GetPresShell();
  if (shell) {
    nsIFrame* frame = shell->FrameManager()->GetRootFrame();
    if(frame) {
      frame->List(out, aIndent);
    }
  }
}
#endif

static void
DestroyAbsoluteContainingBlock(void* aPropertyValue)
{
  delete static_cast<nsAbsoluteContainingBlock*>(aPropertyValue);
}

NS_DECLARE_FRAME_PROPERTY(AbsoluteContainingBlockProperty, DestroyAbsoluteContainingBlock)

bool
nsIFrame::HasAbsolutelyPositionedChildren() const {
  return IsAbsoluteContainer() && GetAbsoluteContainingBlock()->HasAbsoluteFrames();
}

nsAbsoluteContainingBlock*
nsIFrame::GetAbsoluteContainingBlock() const {
  NS_ASSERTION(IsAbsoluteContainer(), "The frame is not marked as an abspos container correctly");
  nsAbsoluteContainingBlock* absCB = static_cast<nsAbsoluteContainingBlock*>
    (Properties().Get(AbsoluteContainingBlockProperty()));
  NS_ASSERTION(absCB, "The frame is marked as an abspos container but doesn't have the property");
  return absCB;
}

void
nsIFrame::MarkAsAbsoluteContainingBlock()
{
  MOZ_ASSERT(GetStateBits() & NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  NS_ASSERTION(!Properties().Get(AbsoluteContainingBlockProperty()),
               "Already has an abs-pos containing block property?");
  NS_ASSERTION(!HasAnyStateBits(NS_FRAME_HAS_ABSPOS_CHILDREN),
               "Already has NS_FRAME_HAS_ABSPOS_CHILDREN state bit?");
  AddStateBits(NS_FRAME_HAS_ABSPOS_CHILDREN);
  Properties().Set(AbsoluteContainingBlockProperty(), new nsAbsoluteContainingBlock(GetAbsoluteListID()));
}

void
nsIFrame::MarkAsNotAbsoluteContainingBlock()
{
  NS_ASSERTION(!HasAbsolutelyPositionedChildren(), "Think of the children!");
  NS_ASSERTION(Properties().Get(AbsoluteContainingBlockProperty()),
               "Should have an abs-pos containing block property");
  NS_ASSERTION(HasAnyStateBits(NS_FRAME_HAS_ABSPOS_CHILDREN),
               "Should have NS_FRAME_HAS_ABSPOS_CHILDREN state bit");
  MOZ_ASSERT(HasAnyStateBits(NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN));
  RemoveStateBits(NS_FRAME_HAS_ABSPOS_CHILDREN);
  Properties().Delete(AbsoluteContainingBlockProperty());
}

bool
nsIFrame::CheckAndClearPaintedState()
{
  bool result = (GetStateBits() & NS_FRAME_PAINTED_THEBES);
  RemoveStateBits(NS_FRAME_PAINTED_THEBES);
  
  nsIFrame::ChildListIterator lists(this);
  for (; !lists.IsDone(); lists.Next()) {
    nsFrameList::Enumerator childFrames(lists.CurrentList());
    for (; !childFrames.AtEnd(); childFrames.Next()) {
      nsIFrame* child = childFrames.get();
      if (child->CheckAndClearPaintedState()) {
        result = true;
      }
    }
  }
  return result;
}

bool
nsIFrame::IsVisibleConsideringAncestors(uint32_t aFlags) const
{
  if (!StyleVisibility()->IsVisible()) {
    return false;
  }

  const nsIFrame* frame = this;
  while (frame) {
    nsView* view = frame->GetView();
    if (view && view->GetVisibility() == nsViewVisibility_kHide)
      return false;
    
    nsIFrame* parent = frame->GetParent();
    nsDeckFrame* deck = do_QueryFrame(parent);
    if (deck) {
      if (deck->GetSelectedBox() != frame)
        return false;
    }

    if (parent) {
      frame = parent;
    } else {
      parent = nsLayoutUtils::GetCrossDocParentFrame(frame);
      if (!parent)
        break;

      if ((aFlags & nsIFrame::VISIBILITY_CROSS_CHROME_CONTENT_BOUNDARY) == 0 &&
          parent->PresContext()->IsChrome() && !frame->PresContext()->IsChrome()) {
        break;
      }

      if (!parent->StyleVisibility()->IsVisible())
        return false;

      frame = parent;
    }
  }

  return true;
}

void
nsIFrame::FindCloserFrameForSelection(
                                 nsPoint aPoint,
                                 nsIFrame::FrameWithDistance* aCurrentBestFrame)
{
  if (nsLayoutUtils::PointIsCloserToRect(aPoint, mRect,
                                         aCurrentBestFrame->mXDistance,
                                         aCurrentBestFrame->mYDistance)) {
    aCurrentBestFrame->mFrame = this;
  }
}

void
NS_MergeReflowStatusInto(nsReflowStatus* aPrimary, nsReflowStatus aSecondary)
{
  *aPrimary |= aSecondary &
    (NS_FRAME_NOT_COMPLETE | NS_FRAME_OVERFLOW_INCOMPLETE |
     NS_FRAME_TRUNCATED | NS_FRAME_REFLOW_NEXTINFLOW);
  if (*aPrimary & NS_FRAME_NOT_COMPLETE) {
    *aPrimary &= ~NS_FRAME_OVERFLOW_INCOMPLETE;
  }
}

void
nsWeakFrame::InitInternal(nsIFrame* aFrame)
{
  Clear(mFrame ? mFrame->PresContext()->GetPresShell() : nullptr);
  mFrame = aFrame;
  if (mFrame) {
    nsIPresShell* shell = mFrame->PresContext()->GetPresShell();
    NS_WARN_IF_FALSE(shell, "Null PresShell in nsWeakFrame!");
    if (shell) {
      shell->AddWeakFrame(this);
    } else {
      mFrame = nullptr;
    }
  }
}

nsIFrame*
NS_NewEmptyFrame(nsIPresShell* aPresShell, nsStyleContext* aContext)
{
  return new (aPresShell) nsFrame(aContext);
}

nsFrame::nsFrame(nsStyleContext* aContext)
{
  MOZ_COUNT_CTOR(nsFrame);

  mState = NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY;
  mStyleContext = aContext;
  mStyleContext->AddRef();
}

nsFrame::~nsFrame()
{
  MOZ_COUNT_DTOR(nsFrame);

  NS_IF_RELEASE(mContent);
  if (mStyleContext)
    mStyleContext->Release();
}

NS_IMPL_FRAMEARENA_HELPERS(nsFrame)

// Dummy operator delete.  Will never be called, but must be defined
// to satisfy some C++ ABIs.
void
nsFrame::operator delete(void *, size_t)
{
  NS_RUNTIMEABORT("nsFrame::operator delete should never be called");
}

NS_QUERYFRAME_HEAD(nsFrame)
  NS_QUERYFRAME_ENTRY(nsIFrame)
NS_QUERYFRAME_TAIL_INHERITANCE_ROOT

/////////////////////////////////////////////////////////////////////////////
// nsIFrame

static bool
IsFontSizeInflationContainer(nsIFrame* aFrame,
                             const nsStyleDisplay* aStyleDisplay)
{
  /*
   * Font size inflation is built around the idea that we're inflating
   * the fonts for a pan-and-zoom UI so that when the user scales up a
   * block or other container to fill the width of the device, the fonts
   * will be readable.  To do this, we need to pick what counts as a
   * container.
   *
   * From a code perspective, the only hard requirement is that frames
   * that are line participants
   * (nsIFrame::IsFrameOfType(nsIFrame::eLineParticipant)) are never
   * containers, since line layout assumes that the inflation is
   * consistent within a line.
   *
   * This is not an imposition, since we obviously want a bunch of text
   * (possibly with inline elements) flowing within a block to count the
   * block (or higher) as its container.
   *
   * We also want form controls, including the text in the anonymous
   * content inside of them, to match each other and the text next to
   * them, so they and their anonymous content should also not be a
   * container.
   *
   * However, because we can't reliably compute sizes across XUL during
   * reflow, any XUL frame with a XUL parent is always a container.
   *
   * There are contexts where it would be nice if some blocks didn't
   * count as a container, so that, for example, an indented quotation
   * didn't end up with a smaller font size.  However, it's hard to
   * distinguish these situations where we really do want the indented
   * thing to count as a container, so we don't try, and blocks are
   * always containers.
   */

  // The root frame should always be an inflation container.
  if (!aFrame->GetParent()) {
    return true;
  }

  nsIContent *content = aFrame->GetContent();
  bool isInline = (aFrame->GetDisplay() == NS_STYLE_DISPLAY_INLINE ||
                   (aFrame->IsFloating() &&
                    aFrame->GetType() == nsGkAtoms::letterFrame) ||
                   // Given multiple frames for the same node, only the
                   // outer one should be considered a container.
                   // (Important, e.g., for nsSelectsAreaFrame.)
                   (aFrame->GetParent()->GetContent() == content) ||
                   (content && (content->IsHTML(nsGkAtoms::option) ||
                                content->IsHTML(nsGkAtoms::optgroup) ||
                                content->IsHTML(nsGkAtoms::select) ||
                                content->IsInNativeAnonymousSubtree()))) &&
                  !(aFrame->IsBoxFrame() && aFrame->GetParent()->IsBoxFrame());
  NS_ASSERTION(!aFrame->IsFrameOfType(nsIFrame::eLineParticipant) ||
               isInline ||
               // br frames and mathml frames report being line
               // participants even when their position or display is
               // set
               aFrame->GetType() == nsGkAtoms::brFrame ||
               aFrame->IsFrameOfType(nsIFrame::eMathML),
               "line participants must not be containers");
  NS_ASSERTION(aFrame->GetType() != nsGkAtoms::bulletFrame || isInline,
               "bullets should not be containers");
  return !isInline;
}

void
nsFrame::Init(nsIContent*      aContent,
              nsIFrame*        aParent,
              nsIFrame*        aPrevInFlow)
{
  NS_PRECONDITION(!mContent, "Double-initing a frame?");
  NS_ASSERTION(IsFrameOfType(eDEBUGAllFrames) &&
               !IsFrameOfType(eDEBUGNoFrames),
               "IsFrameOfType implementation that doesn't call base class");

  mContent = aContent;
  mParent = aParent;

  if (aContent) {
    NS_ADDREF(aContent);
  }

  if (aPrevInFlow) {
    // Make sure the general flags bits are the same
    nsFrameState state = aPrevInFlow->GetStateBits();

    // Make bits that are currently off (see constructor) the same:
    mState |= state & (NS_FRAME_INDEPENDENT_SELECTION |
                       NS_FRAME_IS_SPECIAL |
                       NS_FRAME_MAY_BE_TRANSFORMED |
                       NS_FRAME_MAY_HAVE_GENERATED_CONTENT |
                       NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  }
  if (mParent) {
    nsFrameState state = mParent->GetStateBits();

    // Make bits that are currently off (see constructor) the same:
    mState |= state & (NS_FRAME_INDEPENDENT_SELECTION |
                       NS_FRAME_GENERATED_CONTENT |
                       NS_FRAME_IS_SVG_TEXT |
                       NS_FRAME_IN_POPUP);
  }
  const nsStyleDisplay *disp = StyleDisplay();
  if (disp->HasTransform(this)) {
    // The frame gets reconstructed if we toggle the -moz-transform
    // property, so we can set this bit here and then ignore it.
    mState |= NS_FRAME_MAY_BE_TRANSFORMED;
  }

  if (nsLayoutUtils::FontSizeInflationEnabled(PresContext()) || !GetParent()
#ifdef DEBUG
      // We have assertions that check inflation invariants even when
      // font size inflation is not enabled.
      || true
#endif
      ) {
    if (IsFontSizeInflationContainer(this, disp)) {
      AddStateBits(NS_FRAME_FONT_INFLATION_CONTAINER);
      if (!GetParent() ||
          // I'd use NS_FRAME_OUT_OF_FLOW, but it's not set yet.
          disp->IsFloating(this) || disp->IsAbsolutelyPositioned(this)) {
        AddStateBits(NS_FRAME_FONT_INFLATION_FLOW_ROOT);
      }
    }
    NS_ASSERTION(GetParent() ||
                 (GetStateBits() & NS_FRAME_FONT_INFLATION_CONTAINER),
                 "root frame should always be a container");
  }

  DidSetStyleContext(nullptr);

  if (IsBoxWrapped())
    InitBoxMetrics(false);
}

NS_IMETHODIMP nsFrame::SetInitialChildList(ChildListID     aListID,
                                           nsFrameList&    aChildList)
{
  // XXX This shouldn't be getting called at all, but currently is for backwards
  // compatility reasons...
#if 0
  NS_ERROR("not a container");
  return NS_ERROR_UNEXPECTED;
#else
  NS_ASSERTION(aChildList.IsEmpty(), "not a container");
  return NS_OK;
#endif
}

NS_IMETHODIMP
nsFrame::AppendFrames(ChildListID     aListID,
                      nsFrameList&    aFrameList)
{
  NS_PRECONDITION(false, "not a container");
  return NS_ERROR_UNEXPECTED;
}

NS_IMETHODIMP
nsFrame::InsertFrames(ChildListID     aListID,
                      nsIFrame*       aPrevFrame,
                      nsFrameList&    aFrameList)
{
  NS_PRECONDITION(false, "not a container");
  return NS_ERROR_UNEXPECTED;
}

NS_IMETHODIMP
nsFrame::RemoveFrame(ChildListID     aListID,
                     nsIFrame*       aOldFrame)
{
  NS_PRECONDITION(false, "not a container");
  return NS_ERROR_UNEXPECTED;
}

void
nsFrame::DestroyFrom(nsIFrame* aDestructRoot)
{
  NS_ASSERTION(!nsContentUtils::IsSafeToRunScript(),
    "destroy called on frame while scripts not blocked");
  NS_ASSERTION(!GetNextSibling() && !GetPrevSibling(),
               "Frames should be removed before destruction.");
  NS_ASSERTION(aDestructRoot, "Must specify destruct root");
  MOZ_ASSERT(!HasAbsolutelyPositionedChildren());

  nsSVGEffects::InvalidateDirectRenderingObservers(this);

  // Get the view pointer now before the frame properties disappear
  // when we call NotifyDestroyingFrame()
  nsView* view = GetView();
  nsPresContext* presContext = PresContext();

  nsIPresShell *shell = presContext->GetPresShell();
  if (mState & NS_FRAME_OUT_OF_FLOW) {
    nsPlaceholderFrame* placeholder =
      shell->FrameManager()->GetPlaceholderFrameFor(this);
    NS_ASSERTION(!placeholder || (aDestructRoot != this),
                 "Don't call Destroy() on OOFs, call Destroy() on the placeholder.");
    NS_ASSERTION(!placeholder ||
                 nsLayoutUtils::IsProperAncestorFrame(aDestructRoot, placeholder),
                 "Placeholder relationship should have been torn down already; "
                 "this might mean we have a stray placeholder in the tree.");
    if (placeholder) {
      shell->FrameManager()->UnregisterPlaceholderFrame(placeholder);
      placeholder->SetOutOfFlowFrame(nullptr);
    }
  }

  // If we have any IB split special siblings, clear their references to us.
  // (Note: This has to happen before we call shell->NotifyDestroyingFrame,
  // because that clears our Properties() table.)
  if (mState & NS_FRAME_IS_SPECIAL) {
    // Delete previous sibling's reference to me.
    nsIFrame* prevSib = static_cast<nsIFrame*>
      (Properties().Get(nsIFrame::IBSplitSpecialPrevSibling()));
    if (prevSib) {
      NS_WARN_IF_FALSE(this ==
         prevSib->Properties().Get(nsIFrame::IBSplitSpecialSibling()),
         "IB sibling chain is inconsistent");
      prevSib->Properties().Delete(nsIFrame::IBSplitSpecialSibling());
    }

    // Delete next sibling's reference to me.
    nsIFrame* nextSib = static_cast<nsIFrame*>
      (Properties().Get(nsIFrame::IBSplitSpecialSibling()));
    if (nextSib) {
      NS_WARN_IF_FALSE(this ==
         nextSib->Properties().Get(nsIFrame::IBSplitSpecialPrevSibling()),
         "IB sibling chain is inconsistent");
      nextSib->Properties().Delete(nsIFrame::IBSplitSpecialPrevSibling());
    }
  }

  shell->NotifyDestroyingFrame(this);

  if (mState & NS_FRAME_EXTERNAL_REFERENCE) {
    shell->ClearFrameRefs(this);
  }

  if (view) {
    // Break association between view and frame
    view->SetFrame(nullptr);

    // Destroy the view
    view->Destroy();
  }

  // Make sure that our deleted frame can't be returned from GetPrimaryFrame()
  if (mContent && mContent->GetPrimaryFrame() == this) {
    mContent->SetPrimaryFrame(nullptr);
  }

  // Must retrieve the object ID before calling destructors, so the
  // vtable is still valid.
  //
  // Note to future tweakers: having the method that returns the
  // object size call the destructor will not avoid an indirect call;
  // the compiler cannot devirtualize the call to the destructor even
  // if it's from a method defined in the same class.

  nsQueryFrame::FrameIID id = GetFrameId();
  this->~nsFrame();

  // Now that we're totally cleaned out, we need to add ourselves to
  // the presshell's recycler.
  shell->FreeFrame(id, this);
}

NS_IMETHODIMP
nsFrame::GetOffsets(int32_t &aStart, int32_t &aEnd) const
{
  aStart = 0;
  aEnd = 0;
  return NS_OK;
}

static bool
EqualImages(imgIRequest *aOldImage, imgIRequest *aNewImage)
{
  if (aOldImage == aNewImage)
    return true;

  if (!aOldImage || !aNewImage)
    return false;

  nsCOMPtr<nsIURI> oldURI, newURI;
  aOldImage->GetURI(getter_AddRefs(oldURI));
  aNewImage->GetURI(getter_AddRefs(newURI));
  bool equal;
  return NS_SUCCEEDED(oldURI->Equals(newURI, &equal)) && equal;
}

// Subclass hook for style post processing
/* virtual */ void
nsFrame::DidSetStyleContext(nsStyleContext* aOldStyleContext)
{
  ImageLoader* imageLoader = PresContext()->Document()->StyleImageLoader();

  // If the old context had a background image image and new context
  // does not have the same image, clear the image load notifier
  // (which keeps the image loading, if it still is) for the frame.
  // We want to do this conservatively because some frames paint their
  // backgrounds from some other frame's style data, and we don't want
  // to clear those notifiers unless we have to.  (They'll be reset
  // when we paint, although we could miss a notification in that
  // interval.)
  const nsStyleBackground *oldBG = aOldStyleContext ?
                                   aOldStyleContext->StyleBackground() :
                                   nullptr;
  const nsStyleBackground *newBG = StyleBackground();
  if (oldBG) {
    NS_FOR_VISIBLE_BACKGROUND_LAYERS_BACK_TO_FRONT(i, oldBG) {
      // If there is an image in oldBG that's not in newBG, drop it.
      if (i >= newBG->mImageCount ||
          oldBG->mLayers[i].mImage != newBG->mLayers[i].mImage) {
        const nsStyleImage& oldImage = oldBG->mLayers[i].mImage;
        if (oldImage.GetType() != eStyleImageType_Image) {
          continue;
        }

        imageLoader->DisassociateRequestFromFrame(oldImage.GetImageData(),
                                                  this);
      }          
    }
  }

  NS_FOR_VISIBLE_BACKGROUND_LAYERS_BACK_TO_FRONT(i, newBG) {
    // If there is an image in newBG that's not in oldBG, add it.
    if (!oldBG || i >= oldBG->mImageCount ||
        newBG->mLayers[i].mImage != oldBG->mLayers[i].mImage) {
      const nsStyleImage& newImage = newBG->mLayers[i].mImage;
      if (newImage.GetType() != eStyleImageType_Image) {
        continue;
      }

      imageLoader->AssociateRequestToFrame(newImage.GetImageData(), this);
    }          
  }

  if (aOldStyleContext) {
    // If we detect a change on margin, padding or border, we store the old
    // values on the frame itself between now and reflow, so if someone
    // calls GetUsed(Margin|Border|Padding)() before the next reflow, we
    // can give an accurate answer.
    // We don't want to set the property if one already exists.
    FrameProperties props = Properties();
    nsMargin oldValue(0, 0, 0, 0);
    nsMargin newValue(0, 0, 0, 0);
    const nsStyleMargin* oldMargin = aOldStyleContext->PeekStyleMargin();
    if (oldMargin && oldMargin->GetMargin(oldValue)) {
      if ((!StyleMargin()->GetMargin(newValue) || oldValue != newValue) &&
          !props.Get(UsedMarginProperty())) {
        props.Set(UsedMarginProperty(), new nsMargin(oldValue));
      }
    }

    const nsStylePadding* oldPadding = aOldStyleContext->PeekStylePadding();
    if (oldPadding && oldPadding->GetPadding(oldValue)) {
      if ((!StylePadding()->GetPadding(newValue) || oldValue != newValue) &&
          !props.Get(UsedPaddingProperty())) {
        props.Set(UsedPaddingProperty(), new nsMargin(oldValue));
      }
    }

    const nsStyleBorder* oldBorder = aOldStyleContext->PeekStyleBorder();
    if (oldBorder) {
      oldValue = oldBorder->GetComputedBorder();
      newValue = StyleBorder()->GetComputedBorder();
      if (oldValue != newValue &&
          !props.Get(UsedBorderProperty())) {
        props.Set(UsedBorderProperty(), new nsMargin(oldValue));
      }
    }
  }

  imgIRequest *oldBorderImage = aOldStyleContext
    ? aOldStyleContext->StyleBorder()->GetBorderImage()
    : nullptr;
  imgIRequest *newBorderImage = StyleBorder()->GetBorderImage();
  // FIXME (Bug 759996): The following is no longer true.
  // For border-images, we can't be as conservative (we need to set the
  // new loaders if there has been any change) since the CalcDifference
  // call depended on the result of GetComputedBorder() and that result
  // depends on whether the image has loaded, start the image load now
  // so that we'll get notified when it completes loading and can do a
  // restyle.  Otherwise, the image might finish loading from the
  // network before we start listening to its notifications, and then
  // we'll never know that it's finished loading.  Likewise, we want to
  // do this for freshly-created frames to prevent a similar race if the
  // image loads between reflow (which can depend on whether the image
  // is loaded) and paint.  We also don't really care about any callers
  // who try to paint borders with a different style context, because
  // they won't have the correct size for the border either.
  if (!EqualImages(oldBorderImage, newBorderImage)) {
    // stop and restart the image loading/notification
    if (oldBorderImage) {
      imageLoader->DisassociateRequestFromFrame(oldBorderImage, this);
    }
    if (newBorderImage) {
      imageLoader->AssociateRequestToFrame(newBorderImage, this);
    }
  }

  // If the page contains markup that overrides text direction, and
  // does not contain any characters that would activate the Unicode
  // bidi algorithm, we need to call |SetBidiEnabled| on the pres
  // context before reflow starts.  See bug 115921.
  if (StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL) {
    PresContext()->SetBidiEnabled();
  }
}

// MSVC fails with link error "one or more multiply defined symbols found",
// gcc fails with "hidden symbol `nsIFrame::kPrincipalList' isn't defined"
// etc if they are not defined.
#ifndef _MSC_VER
// static nsIFrame constants; initialized in the header file.
const nsIFrame::ChildListID nsIFrame::kPrincipalList;
const nsIFrame::ChildListID nsIFrame::kAbsoluteList;
const nsIFrame::ChildListID nsIFrame::kBulletList;
const nsIFrame::ChildListID nsIFrame::kCaptionList;
const nsIFrame::ChildListID nsIFrame::kColGroupList;
const nsIFrame::ChildListID nsIFrame::kExcessOverflowContainersList;
const nsIFrame::ChildListID nsIFrame::kFixedList;
const nsIFrame::ChildListID nsIFrame::kFloatList;
const nsIFrame::ChildListID nsIFrame::kOverflowContainersList;
const nsIFrame::ChildListID nsIFrame::kOverflowList;
const nsIFrame::ChildListID nsIFrame::kOverflowOutOfFlowList;
const nsIFrame::ChildListID nsIFrame::kPopupList;
const nsIFrame::ChildListID nsIFrame::kPushedFloatsList;
const nsIFrame::ChildListID nsIFrame::kSelectPopupList;
const nsIFrame::ChildListID nsIFrame::kNoReflowPrincipalList;
#endif

/* virtual */ nsMargin
nsIFrame::GetUsedMargin() const
{
  nsMargin margin(0, 0, 0, 0);
  if (((mState & NS_FRAME_FIRST_REFLOW) &&
       !(mState & NS_FRAME_IN_REFLOW)) ||
      IsSVGText())
    return margin;

  nsMargin *m = static_cast<nsMargin*>
                           (Properties().Get(UsedMarginProperty()));
  if (m) {
    margin = *m;
  } else {
#ifdef DEBUG
    bool hasMargin = 
#endif
    StyleMargin()->GetMargin(margin);
    NS_ASSERTION(hasMargin, "We should have a margin here! (out of memory?)");
  }
  return margin;
}

/* virtual */ nsMargin
nsIFrame::GetUsedBorder() const
{
  nsMargin border(0, 0, 0, 0);
  if (((mState & NS_FRAME_FIRST_REFLOW) &&
       !(mState & NS_FRAME_IN_REFLOW)) ||
      IsSVGText())
    return border;

  // Theme methods don't use const-ness.
  nsIFrame *mutable_this = const_cast<nsIFrame*>(this);

  const nsStyleDisplay *disp = StyleDisplay();
  if (mutable_this->IsThemed(disp)) {
    nsIntMargin result;
    nsPresContext *presContext = PresContext();
    presContext->GetTheme()->GetWidgetBorder(presContext->DeviceContext(),
                                             mutable_this, disp->mAppearance,
                                             &result);
    border.left = presContext->DevPixelsToAppUnits(result.left);
    border.top = presContext->DevPixelsToAppUnits(result.top);
    border.right = presContext->DevPixelsToAppUnits(result.right);
    border.bottom = presContext->DevPixelsToAppUnits(result.bottom);
    return border;
  }

  nsMargin *b = static_cast<nsMargin*>
                           (Properties().Get(UsedBorderProperty()));
  if (b) {
    border = *b;
  } else {
    border = StyleBorder()->GetComputedBorder();
  }
  return border;
}

/* virtual */ nsMargin
nsIFrame::GetUsedPadding() const
{
  nsMargin padding(0, 0, 0, 0);
  if (((mState & NS_FRAME_FIRST_REFLOW) &&
       !(mState & NS_FRAME_IN_REFLOW)) ||
      IsSVGText())
    return padding;

  // Theme methods don't use const-ness.
  nsIFrame *mutable_this = const_cast<nsIFrame*>(this);

  const nsStyleDisplay *disp = StyleDisplay();
  if (mutable_this->IsThemed(disp)) {
    nsPresContext *presContext = PresContext();
    nsIntMargin widget;
    if (presContext->GetTheme()->GetWidgetPadding(presContext->DeviceContext(),
                                                  mutable_this,
                                                  disp->mAppearance,
                                                  &widget)) {
      padding.top = presContext->DevPixelsToAppUnits(widget.top);
      padding.right = presContext->DevPixelsToAppUnits(widget.right);
      padding.bottom = presContext->DevPixelsToAppUnits(widget.bottom);
      padding.left = presContext->DevPixelsToAppUnits(widget.left);
      return padding;
    }
  }

  nsMargin *p = static_cast<nsMargin*>
                           (Properties().Get(UsedPaddingProperty()));
  if (p) {
    padding = *p;
  } else {
#ifdef DEBUG
    bool hasPadding = 
#endif
    StylePadding()->GetPadding(padding);
    NS_ASSERTION(hasPadding, "We should have padding here! (out of memory?)");
  }
  return padding;
}

void
nsIFrame::ApplySkipSides(nsMargin& aMargin) const
{
  int skipSides = GetSkipSides();
  if (skipSides & (1 << NS_SIDE_TOP))
    aMargin.top = 0;
  if (skipSides & (1 << NS_SIDE_RIGHT))
    aMargin.right = 0;
  if (skipSides & (1 << NS_SIDE_BOTTOM))
    aMargin.bottom = 0;
  if (skipSides & (1 << NS_SIDE_LEFT))
    aMargin.left = 0;
}

nsRect
nsIFrame::GetPaddingRectRelativeToSelf() const
{
  nsMargin bp(GetUsedBorder());
  ApplySkipSides(bp);
  nsRect r(0, 0, mRect.width, mRect.height);
  r.Deflate(bp);
  return r;
}

nsRect
nsIFrame::GetPaddingRect() const
{
  return GetPaddingRectRelativeToSelf() + GetPosition();
}

bool
nsIFrame::IsTransformed() const
{
  return ((mState & NS_FRAME_MAY_BE_TRANSFORMED) &&
          (StyleDisplay()->HasTransform(this) ||
           IsSVGTransformed() ||
           (mContent &&
            nsLayoutUtils::HasAnimationsForCompositor(mContent,
                                                      eCSSProperty_transform) &&
            IsFrameOfType(eSupportsCSSTransforms) &&
            mContent->GetPrimaryFrame() == this)));
}

bool
nsIFrame::HasOpacity() const
{
  return StyleDisplay()->mOpacity < 1.0f || (mContent &&
           nsLayoutUtils::HasAnimationsForCompositor(mContent,
                                                     eCSSProperty_opacity) &&
           mContent->GetPrimaryFrame() == this);
}

bool
nsIFrame::IsSVGTransformed(gfxMatrix *aOwnTransforms,
                           gfxMatrix *aFromParentTransforms) const
{
  return false;
}

bool
nsIFrame::Preserves3DChildren() const
{
  if (StyleDisplay()->mTransformStyle != NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D ||
      !StyleDisplay()->HasTransform(this))
      return false;

  // If we're all scroll frame, then all descendants will be clipped, so we can't preserve 3d.
  if (GetType() == nsGkAtoms::scrollFrame)
      return false;

  nsRect temp;
  const nsStyleDisplay* displayStyle = StyleDisplay();
  return !nsFrame::ShouldApplyOverflowClipping(this, displayStyle) &&
         !GetClipPropClipRect(displayStyle, &temp, GetSize()) &&
         !nsSVGIntegrationUtils::UsingEffectsForFrame(this);
}

bool
nsIFrame::Preserves3D() const
{
  if (!GetParent() || !GetParent()->Preserves3DChildren() ||
      !StyleDisplay()->HasTransform(this)) {
    return false;
  }
  return true;
}

bool
nsIFrame::HasPerspective() const
{
  if (!IsTransformed()) {
    return false;
  }
  const nsStyleDisplay* parentDisp = nullptr;
  nsStyleContext* parentStyleContext = StyleContext()->GetParent();
  if (parentStyleContext) {
    parentDisp = parentStyleContext->StyleDisplay();
  }

  if (parentDisp &&
      parentDisp->mChildPerspective.GetUnit() == eStyleUnit_Coord &&
      parentDisp->mChildPerspective.GetCoordValue() > 0.0) {
    return true;
  }
  return false;
}

bool
nsIFrame::ChildrenHavePerspective() const
{
  const nsStyleDisplay *disp = StyleDisplay();
  if (disp &&
      disp->mChildPerspective.GetUnit() == eStyleUnit_Coord &&
      disp->mChildPerspective.GetCoordValue() > 0.0) {
    return true;
  }
  return false;
}

nsRect
nsIFrame::GetContentRectRelativeToSelf() const
{
  nsMargin bp(GetUsedBorderAndPadding());
  ApplySkipSides(bp);
  nsRect r(0, 0, mRect.width, mRect.height);
  r.Deflate(bp);
  return r;
}

nsRect
nsIFrame::GetContentRect() const
{
  return GetContentRectRelativeToSelf() + GetPosition();
}

bool
nsIFrame::ComputeBorderRadii(const nsStyleCorners& aBorderRadius,
                             const nsSize& aFrameSize,
                             const nsSize& aBorderArea,
                             int aSkipSides,
                             nscoord aRadii[8])
{
  // Percentages are relative to whichever side they're on.
  NS_FOR_CSS_HALF_CORNERS(i) {
    const nsStyleCoord c = aBorderRadius.Get(i);
    nscoord axis =
      NS_HALF_CORNER_IS_X(i) ? aFrameSize.width : aFrameSize.height;

    if (c.IsCoordPercentCalcUnit()) {
      aRadii[i] = nsRuleNode::ComputeCoordPercentCalc(c, axis);
      if (aRadii[i] < 0) {
        // clamp calc()
        aRadii[i] = 0;
      }
    } else {
      NS_NOTREACHED("ComputeBorderRadii: bad unit");
      aRadii[i] = 0;
    }
  }

  if (aSkipSides & (1 << NS_SIDE_TOP)) {
    aRadii[NS_CORNER_TOP_LEFT_X] = 0;
    aRadii[NS_CORNER_TOP_LEFT_Y] = 0;
    aRadii[NS_CORNER_TOP_RIGHT_X] = 0;
    aRadii[NS_CORNER_TOP_RIGHT_Y] = 0;
  }

  if (aSkipSides & (1 << NS_SIDE_RIGHT)) {
    aRadii[NS_CORNER_TOP_RIGHT_X] = 0;
    aRadii[NS_CORNER_TOP_RIGHT_Y] = 0;
    aRadii[NS_CORNER_BOTTOM_RIGHT_X] = 0;
    aRadii[NS_CORNER_BOTTOM_RIGHT_Y] = 0;
  }

  if (aSkipSides & (1 << NS_SIDE_BOTTOM)) {
    aRadii[NS_CORNER_BOTTOM_RIGHT_X] = 0;
    aRadii[NS_CORNER_BOTTOM_RIGHT_Y] = 0;
    aRadii[NS_CORNER_BOTTOM_LEFT_X] = 0;
    aRadii[NS_CORNER_BOTTOM_LEFT_Y] = 0;
  }

  if (aSkipSides & (1 << NS_SIDE_LEFT)) {
    aRadii[NS_CORNER_BOTTOM_LEFT_X] = 0;
    aRadii[NS_CORNER_BOTTOM_LEFT_Y] = 0;
    aRadii[NS_CORNER_TOP_LEFT_X] = 0;
    aRadii[NS_CORNER_TOP_LEFT_Y] = 0;
  }

  // css3-background specifies this algorithm for reducing
  // corner radii when they are too big.
  bool haveRadius = false;
  double ratio = 1.0f;
  NS_FOR_CSS_SIDES(side) {
    uint32_t hc1 = NS_SIDE_TO_HALF_CORNER(side, false, true);
    uint32_t hc2 = NS_SIDE_TO_HALF_CORNER(side, true, true);
    nscoord length =
      NS_SIDE_IS_VERTICAL(side) ? aBorderArea.height : aBorderArea.width;
    nscoord sum = aRadii[hc1] + aRadii[hc2];
    if (sum)
      haveRadius = true;

    // avoid floating point division in the normal case
    if (length < sum)
      ratio = std::min(ratio, double(length)/sum);
  }
  if (ratio < 1.0) {
    NS_FOR_CSS_HALF_CORNERS(corner) {
      aRadii[corner] *= ratio;
    }
  }

  return haveRadius;
}

/* static */ void
nsIFrame::InsetBorderRadii(nscoord aRadii[8], const nsMargin &aOffsets)
{
  NS_FOR_CSS_SIDES(side) {
    nscoord offset = aOffsets.Side(side);
    uint32_t hc1 = NS_SIDE_TO_HALF_CORNER(side, false, false);
    uint32_t hc2 = NS_SIDE_TO_HALF_CORNER(side, true, false);
    aRadii[hc1] = std::max(0, aRadii[hc1] - offset);
    aRadii[hc2] = std::max(0, aRadii[hc2] - offset);
  }
}

/* static */ void
nsIFrame::OutsetBorderRadii(nscoord aRadii[8], const nsMargin &aOffsets)
{
  NS_FOR_CSS_SIDES(side) {
    nscoord offset = aOffsets.Side(side);
    uint32_t hc1 = NS_SIDE_TO_HALF_CORNER(side, false, false);
    uint32_t hc2 = NS_SIDE_TO_HALF_CORNER(side, true, false);
    if (aRadii[hc1] > 0)
      aRadii[hc1] += offset;
    if (aRadii[hc2] > 0)
      aRadii[hc2] += offset;
  }
}

/* virtual */ bool
nsIFrame::GetBorderRadii(nscoord aRadii[8]) const
{
  if (IsThemed()) {
    // When we're themed, the native theme code draws the border and
    // background, and therefore it doesn't make sense to tell other
    // code that's interested in border-radius that we have any radii.
    //
    // In an ideal world, we might have a way for the them to tell us an
    // border radius, but since we don't, we're better off assuming
    // zero.
    NS_FOR_CSS_HALF_CORNERS(corner) {
      aRadii[corner] = 0;
    }
    return false;
  }
  nsSize size = GetSize();
  return ComputeBorderRadii(StyleBorder()->mBorderRadius, size, size,
                            GetSkipSides(), aRadii);
}

bool
nsIFrame::GetPaddingBoxBorderRadii(nscoord aRadii[8]) const
{
  if (!GetBorderRadii(aRadii))
    return false;
  InsetBorderRadii(aRadii, GetUsedBorder());
  NS_FOR_CSS_HALF_CORNERS(corner) {
    if (aRadii[corner])
      return true;
  }
  return false;
}

bool
nsIFrame::GetContentBoxBorderRadii(nscoord aRadii[8]) const
{
  if (!GetBorderRadii(aRadii))
    return false;
  InsetBorderRadii(aRadii, GetUsedBorderAndPadding());
  NS_FOR_CSS_HALF_CORNERS(corner) {
    if (aRadii[corner])
      return true;
  }
  return false;
}

nsStyleContext*
nsFrame::GetAdditionalStyleContext(int32_t aIndex) const
{
  NS_PRECONDITION(aIndex >= 0, "invalid index number");
  return nullptr;
}

void
nsFrame::SetAdditionalStyleContext(int32_t aIndex, 
                                   nsStyleContext* aStyleContext)
{
  NS_PRECONDITION(aIndex >= 0, "invalid index number");
}

nscoord
nsFrame::GetBaseline() const
{
  NS_ASSERTION(!NS_SUBTREE_DIRTY(this),
               "frame must not be dirty");
  // Default to the bottom margin edge, per CSS2.1's definition of the
  // 'baseline' value of 'vertical-align'.
  return mRect.height + GetUsedMargin().bottom;
}

const nsFrameList&
nsFrame::GetChildList(ChildListID aListID) const
{
  if (IsAbsoluteContainer() &&
      aListID == GetAbsoluteListID()) {
    return GetAbsoluteContainingBlock()->GetChildList();
  } else {
    return nsFrameList::EmptyList();
  }
}

void
nsFrame::GetChildLists(nsTArray<ChildList>* aLists) const
{
  if (IsAbsoluteContainer()) {
    nsFrameList absoluteList = GetAbsoluteContainingBlock()->GetChildList();
    absoluteList.AppendIfNonempty(aLists, GetAbsoluteListID());
  }
}

void
nsIFrame::GetCrossDocChildLists(nsTArray<ChildList>* aLists)
{
  nsSubDocumentFrame* subdocumentFrame = do_QueryFrame(this);
  if (subdocumentFrame) {
    // Descend into the subdocument
    nsIFrame* root = subdocumentFrame->GetSubdocumentRootFrame();
    if (root) {
      aLists->AppendElement(nsIFrame::ChildList(
        nsFrameList(root, nsLayoutUtils::GetLastSibling(root)),
        nsIFrame::kPrincipalList));
    }
  }

  GetChildLists(aLists);
}

static nsIFrame*
GetActiveSelectionFrame(nsPresContext* aPresContext, nsIFrame* aFrame)
{
  nsIContent* capturingContent = nsIPresShell::GetCapturingContent();
  if (capturingContent) {
    nsIFrame* activeFrame = aPresContext->GetPrimaryFrameFor(capturingContent);
    return activeFrame ? activeFrame : aFrame;
  }

  return aFrame;
}

int16_t
nsFrame::DisplaySelection(nsPresContext* aPresContext, bool isOkToTurnOn)
{
  int16_t selType = nsISelectionController::SELECTION_OFF;

  nsCOMPtr<nsISelectionController> selCon;
  nsresult result = GetSelectionController(aPresContext, getter_AddRefs(selCon));
  if (NS_SUCCEEDED(result) && selCon) {
    result = selCon->GetDisplaySelection(&selType);
    if (NS_SUCCEEDED(result) && (selType != nsISelectionController::SELECTION_OFF)) {
      // Check whether style allows selection.
      bool selectable;
      IsSelectable(&selectable, nullptr);
      if (!selectable) {
        selType = nsISelectionController::SELECTION_OFF;
        isOkToTurnOn = false;
      }
    }
    if (isOkToTurnOn && (selType == nsISelectionController::SELECTION_OFF)) {
      selCon->SetDisplaySelection(nsISelectionController::SELECTION_ON);
      selType = nsISelectionController::SELECTION_ON;
    }
  }
  return selType;
}

class nsDisplaySelectionOverlay : public nsDisplayItem {
public:
  nsDisplaySelectionOverlay(nsDisplayListBuilder* aBuilder,
                            nsFrame* aFrame, int16_t aSelectionValue)
    : nsDisplayItem(aBuilder, aFrame), mSelectionValue(aSelectionValue) {
    MOZ_COUNT_CTOR(nsDisplaySelectionOverlay);
  }
#ifdef NS_BUILD_REFCNT_LOGGING
  virtual ~nsDisplaySelectionOverlay() {
    MOZ_COUNT_DTOR(nsDisplaySelectionOverlay);
  }
#endif

  virtual void Paint(nsDisplayListBuilder* aBuilder,
                     nsRenderingContext* aCtx);
  NS_DISPLAY_DECL_NAME("SelectionOverlay", TYPE_SELECTION_OVERLAY)
private:
  int16_t mSelectionValue;
};

void nsDisplaySelectionOverlay::Paint(nsDisplayListBuilder* aBuilder,
                                      nsRenderingContext* aCtx)
{
  LookAndFeel::ColorID colorID;
  if (mSelectionValue == nsISelectionController::SELECTION_ON) {
    colorID = LookAndFeel::eColorID_TextSelectBackground;
  } else if (mSelectionValue == nsISelectionController::SELECTION_ATTENTION) {
    colorID = LookAndFeel::eColorID_TextSelectBackgroundAttention;
  } else {
    colorID = LookAndFeel::eColorID_TextSelectBackgroundDisabled;
  }

  nscolor color = LookAndFeel::GetColor(colorID, NS_RGB(255, 255, 255));

  gfxRGBA c(color);
  c.a = .5;

  gfxContext *ctx = aCtx->ThebesContext();
  ctx->SetColor(c);

  nsIntRect pxRect =
    mVisibleRect.ToOutsidePixels(mFrame->PresContext()->AppUnitsPerDevPixel());
  ctx->NewPath();
  ctx->Rectangle(gfxRect(pxRect.x, pxRect.y, pxRect.width, pxRect.height), true);
  ctx->Fill();
}

/********************************************************
* Refreshes each content's frame
*********************************************************/

void
nsFrame::DisplaySelectionOverlay(nsDisplayListBuilder*   aBuilder,
                                 nsDisplayList*          aList,
                                 uint16_t                aContentType)
{
  if (!IsSelected() || !IsVisibleForPainting(aBuilder))
    return;
    
  nsPresContext* presContext = PresContext();
  nsIPresShell *shell = presContext->PresShell();
  if (!shell)
    return;

  int16_t displaySelection = shell->GetSelectionFlags();
  if (!(displaySelection & aContentType))
    return;

  const nsFrameSelection* frameSelection = GetConstFrameSelection();
  int16_t selectionValue = frameSelection->GetDisplaySelection();

  if (selectionValue <= nsISelectionController::SELECTION_HIDDEN)
    return; // selection is hidden or off

  nsIContent *newContent = mContent->GetParent();

  //check to see if we are anonymous content
  int32_t offset = 0;
  if (newContent) {
    // XXXbz there has GOT to be a better way of determining this!
    offset = newContent->IndexOf(mContent);
  }

  SelectionDetails *details;
  //look up to see what selection(s) are on this frame
  details = frameSelection->LookUpSelection(newContent, offset, 1, false);
  if (!details)
    return;
  
  bool normal = false;
  while (details) {
    if (details->mType == nsISelectionController::SELECTION_NORMAL) {
      normal = true;
    }
    SelectionDetails *next = details->mNext;
    delete details;
    details = next;
  }

  if (!normal && aContentType == nsISelectionDisplay::DISPLAY_IMAGES) {
    // Don't overlay an image if it's not in the primary selection.
    return;
  }

  aList->AppendNewToTop(new (aBuilder)
    nsDisplaySelectionOverlay(aBuilder, this, selectionValue));
}

void
nsFrame::DisplayOutlineUnconditional(nsDisplayListBuilder*   aBuilder,
                                     const nsDisplayListSet& aLists)
{
  if (StyleOutline()->GetOutlineStyle() == NS_STYLE_BORDER_STYLE_NONE)
    return;

  aLists.Outlines()->AppendNewToTop(
    new (aBuilder) nsDisplayOutline(aBuilder, this));
}

void
nsFrame::DisplayOutline(nsDisplayListBuilder*   aBuilder,
                        const nsDisplayListSet& aLists)
{
  if (!IsVisibleForPainting(aBuilder))
    return;

  DisplayOutlineUnconditional(aBuilder, aLists);
}

void
nsIFrame::DisplayCaret(nsDisplayListBuilder* aBuilder,
                       const nsRect& aDirtyRect, nsDisplayList* aList)
{
  if (!IsVisibleForPainting(aBuilder))
    return;

  aList->AppendNewToTop(
    new (aBuilder) nsDisplayCaret(aBuilder, this, aBuilder->GetCaret()));
}

nscolor
nsIFrame::GetCaretColorAt(int32_t aOffset)
{
  // Use text color.
  return StyleColor()->mColor;
}

void
nsFrame::DisplayBackgroundUnconditional(nsDisplayListBuilder*       aBuilder,
                                        const nsDisplayListSet&     aLists,
                                        bool                        aForceBackground,
                                        nsDisplayBackgroundImage** aBackground)
{
  *aBackground = nullptr;

  // Here we don't try to detect background propagation. Frames that might
  // receive a propagated background should just set aForceBackground to
  // true.
  if (aBuilder->IsForEventDelivery() || aForceBackground ||
      !StyleBackground()->IsTransparent() || StyleDisplay()->mAppearance) {
    nsDisplayBackgroundImage::AppendBackgroundItemsToTop(aBuilder, this,
                                                         aLists.BorderBackground(),
                                                         aBackground);
  }
}

void
nsFrame::DisplayBorderBackgroundOutline(nsDisplayListBuilder*   aBuilder,
                                        const nsDisplayListSet& aLists,
                                        bool                    aForceBackground)
{
  // The visibility check belongs here since child elements have the
  // opportunity to override the visibility property and display even if
  // their parent is hidden.
  if (!IsVisibleForPainting(aBuilder))
    return;

  nsCSSShadowArray* shadows = StyleBorder()->mBoxShadow;
  if (shadows && shadows->HasShadowWithInset(false)) {
    aLists.BorderBackground()->AppendNewToTop(new (aBuilder)
      nsDisplayBoxShadowOuter(aBuilder, this));
  }

  nsDisplayBackgroundImage* bg;
  DisplayBackgroundUnconditional(aBuilder, aLists, aForceBackground, &bg);

  if (shadows && shadows->HasShadowWithInset(true)) {
    aLists.BorderBackground()->AppendNewToTop(new (aBuilder)
      nsDisplayBoxShadowInner(aBuilder, this));
  }

  // If there's a themed background, we should not create a border item.
  // It won't be rendered.
  if ((!bg || !bg->IsThemed()) && StyleBorder()->HasBorder()) {
    aLists.BorderBackground()->AppendNewToTop(new (aBuilder)
      nsDisplayBorder(aBuilder, this));
  }

  DisplayOutlineUnconditional(aBuilder, aLists);
}

inline static bool IsSVGContentWithCSSClip(const nsIFrame *aFrame)
{
  // The CSS spec says that the 'clip' property only applies to absolutely
  // positioned elements, whereas the SVG spec says that it applies to SVG
  // elements regardless of the value of the 'position' property. Here we obey
  // the CSS spec for outer-<svg> (since that's what we generally do), but
  // obey the SVG spec for other SVG elements to which 'clip' applies.
  nsIAtom *tag = aFrame->GetContent()->Tag();
  return (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT) &&
    (tag == nsGkAtoms::svg || tag == nsGkAtoms::foreignObject);
}

bool
nsIFrame::GetClipPropClipRect(const nsStyleDisplay* aDisp, nsRect* aRect,
                              const nsSize& aSize) const
{
  NS_PRECONDITION(aRect, "Must have aRect out parameter");

  if (!(aDisp->mClipFlags & NS_STYLE_CLIP_RECT) ||
      !(aDisp->IsAbsolutelyPositioned(this) || IsSVGContentWithCSSClip(this))) {
    return false;
  }

  *aRect = aDisp->mClip;
  if (NS_STYLE_CLIP_RIGHT_AUTO & aDisp->mClipFlags) {
    aRect->width = aSize.width - aRect->x;
  }
  if (NS_STYLE_CLIP_BOTTOM_AUTO & aDisp->mClipFlags) {
    aRect->height = aSize.height - aRect->y;
  }
  return true;
}

/**
 * If the CSS 'clip' property applies to this frame, set it up
 * in aBuilder->ClipState() to clip all content descendants. Returns true
 * if the property applies, and if so also returns the clip rect (relative
 * to aFrame) in *aRect.
 */
static bool
ApplyClipPropClipping(nsDisplayListBuilder* aBuilder,
                      const nsIFrame* aFrame,
                      const nsStyleDisplay* aDisp,
                      nsRect* aRect,
                      DisplayListClipState::AutoSaveRestore& aClipState)
{
  if (!aFrame->GetClipPropClipRect(aDisp, aRect, aFrame->GetSize()))
    return false;

  nsRect clipRect = *aRect + aBuilder->ToReferenceFrame(aFrame);
  aClipState.ClipContentDescendants(clipRect);
  return true;
}

/**
 * If the CSS 'overflow' property applies to this frame, and is not
 * handled by constructing a dedicated nsHTML/XULScrollFrame, set up clipping
 * for that overflow in aBuilder->ClipState() to clip all containing-block
 * descendants.
 */
static void
ApplyOverflowClipping(nsDisplayListBuilder* aBuilder,
                      const nsIFrame* aFrame,
                      const nsStyleDisplay* aDisp,
                      DisplayListClipState::AutoClipMultiple& aClipState)
{
  // Only -moz-hidden-unscrollable is handled here (and 'hidden' for table
  // frames, and any non-visible value for blocks in a paginated context).
  // We allow -moz-hidden-unscrollable to apply to any kind of frame. This
  // is required by comboboxes which make their display text (an inline frame)
  // have clipping.
  if (!nsFrame::ShouldApplyOverflowClipping(aFrame, aDisp)) {
    return;
  }
  nsRect rect = aFrame->GetPaddingRectRelativeToSelf() +
      aBuilder->ToReferenceFrame(aFrame);
  nscoord radii[8];
  bool haveRadii = aFrame->GetPaddingBoxBorderRadii(radii);
  aClipState.ClipContainingBlockDescendantsExtra(rect, haveRadii ? radii : nullptr);
}

#ifdef DEBUG
static void PaintDebugBorder(nsIFrame* aFrame, nsRenderingContext* aCtx,
     const nsRect& aDirtyRect, nsPoint aPt) {
  nsRect r(aPt, aFrame->GetSize());
  if (aFrame->HasView()) {
    aCtx->SetColor(NS_RGB(0,0,255));
  } else {
    aCtx->SetColor(NS_RGB(255,0,0));
  }
  aCtx->DrawRect(r);
}

static void PaintEventTargetBorder(nsIFrame* aFrame, nsRenderingContext* aCtx,
     const nsRect& aDirtyRect, nsPoint aPt) {
  nsRect r(aPt, aFrame->GetSize());
  aCtx->SetColor(NS_RGB(128,0,128));
  aCtx->DrawRect(r);
}

static void
DisplayDebugBorders(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                    const nsDisplayListSet& aLists) {
  // Draw a border around the child
  // REVIEW: From nsContainerFrame::PaintChild
  if (nsFrame::GetShowFrameBorders() && !aFrame->GetRect().IsEmpty()) {
    aLists.Outlines()->AppendNewToTop(new (aBuilder)
        nsDisplayGeneric(aBuilder, aFrame, PaintDebugBorder, "DebugBorder",
                         nsDisplayItem::TYPE_DEBUG_BORDER));
  }
  // Draw a border around the current event target
  if (nsFrame::GetShowEventTargetFrameBorder() &&
      aFrame->PresContext()->PresShell()->GetDrawEventTargetFrame() == aFrame) {
    aLists.Outlines()->AppendNewToTop(new (aBuilder)
        nsDisplayGeneric(aBuilder, aFrame, PaintEventTargetBorder, "EventTargetBorder",
                         nsDisplayItem::TYPE_EVENT_TARGET_BORDER));
  }
}
#endif

static nsresult
WrapPreserve3DListInternal(nsIFrame* aFrame, nsDisplayListBuilder *aBuilder, nsDisplayList *aList, nsDisplayList *aOutput, uint32_t& aIndex, nsDisplayList* aTemp)
{
  if (aIndex > nsDisplayTransform::INDEX_MAX) {
    return NS_OK;
  }

  nsresult rv = NS_OK;
  while (nsDisplayItem *item = aList->RemoveBottom()) {
    nsIFrame *childFrame = item->GetUnderlyingFrame();

    // We accumulate sequential items that aren't transforms into the 'temp' list
    // and then flush this list into aOutput by wrapping the whole lot with a single
    // nsDisplayTransform.

    if (childFrame && (childFrame->GetParent()->Preserves3DChildren() || childFrame == aFrame)) {
      switch (item->GetType()) {
        case nsDisplayItem::TYPE_TRANSFORM: {
          if (!aTemp->IsEmpty()) {
            aOutput->AppendToTop(new (aBuilder) nsDisplayTransform(aBuilder, aFrame, aTemp, aIndex++));
          }
          aOutput->AppendToTop(item);
          break;
        }
        case nsDisplayItem::TYPE_WRAP_LIST: {
          nsDisplayWrapList *list = static_cast<nsDisplayWrapList*>(item);
          rv = WrapPreserve3DListInternal(aFrame, aBuilder,
              list->GetChildren(), aOutput, aIndex, aTemp);
          list->~nsDisplayWrapList();
          break;
        }
        case nsDisplayItem::TYPE_OPACITY: {
          if (!aTemp->IsEmpty()) {
            aOutput->AppendToTop(new (aBuilder) nsDisplayTransform(aBuilder, aFrame, aTemp, aIndex++));
          }
          nsDisplayOpacity *opacity = static_cast<nsDisplayOpacity*>(item);
          nsDisplayList output;
          // Call GetChildren, not GetSameCoordinateSystemChildren, because
          // the preserve-3d children of 'opacity' are temporarily not in the
          // same coordinate system as the opacity --- until this wrapping is done.
          rv = WrapPreserve3DListInternal(aFrame, aBuilder,
              opacity->GetChildren(), &output, aIndex, aTemp);
          if (!aTemp->IsEmpty()) {
            output.AppendToTop(new (aBuilder) nsDisplayTransform(aBuilder, aFrame, aTemp, aIndex++));
          }
          opacity->GetChildren()->AppendToTop(&output);
          opacity->UpdateBounds(aBuilder);
          aOutput->AppendToTop(item);
          break;
        }
        default: {
          aTemp->AppendToTop(item);
          break;
        }
      } 
    } else {
      aTemp->AppendToTop(item);
    }
 
    if (NS_FAILED(rv) || !item || aIndex > nsDisplayTransform::INDEX_MAX)
      return rv;
  }
    
  return NS_OK;
}

static nsresult
WrapPreserve3DList(nsIFrame* aFrame, nsDisplayListBuilder* aBuilder, nsDisplayList *aList)
{
  uint32_t index = 0;
  nsDisplayList temp;
  nsDisplayList output;
  nsresult rv = WrapPreserve3DListInternal(aFrame, aBuilder, aList, &output, index, &temp);

  if (!temp.IsEmpty()) {
    output.AppendToTop(new (aBuilder) nsDisplayTransform(aBuilder, aFrame, &temp, index++));
  }

  aList->AppendToTop(&output);
  return rv;
}

void
nsIFrame::BuildDisplayListForStackingContext(nsDisplayListBuilder* aBuilder,
                                             const nsRect&         aDirtyRect,
                                             nsDisplayList*        aList) {
  if (GetStateBits() & NS_FRAME_TOO_DEEP_IN_FRAME_TREE)
    return;

  // Replaced elements have their visibility handled here, because
  // they're visually atomic
  if (IsFrameOfType(eReplaced) && !IsVisibleForPainting(aBuilder))
    return;

  const nsStyleDisplay* disp = StyleDisplay();
  // We can stop right away if this is a zero-opacity stacking context and
  // we're painting, and we're not animating opacity. Don't do this
  // if we're going to compute plugin geometry, since opacity-0 plugins
  // need to have display items built for them.
  if (disp->mOpacity == 0.0 && aBuilder->IsForPainting() &&
      !aBuilder->WillComputePluginGeometry() &&
      !nsLayoutUtils::HasAnimationsForCompositor(mContent,
                                                 eCSSProperty_opacity)) {
    return;
  }

  nsRect dirtyRect = aDirtyRect;

  bool inTransform = aBuilder->IsInTransform();
  bool isTransformed = IsTransformed();
  if (isTransformed) {
    if (aBuilder->IsForPainting() &&
        nsDisplayTransform::ShouldPrerenderTransformedContent(aBuilder, this)) {
      dirtyRect = GetVisualOverflowRectRelativeToSelf();
    } else {
      // Trying to  back-transform arbitrary rects gives us really weird results. I believe 
      // this is from points that lie beyond the vanishing point. As a workaround we transform t
      // he overflow rect into screen space and compare in that coordinate system.

      // Transform the overflow rect into screen space
      nsRect overflow = GetVisualOverflowRectRelativeToSelf();
      nsPoint offset = aBuilder->ToReferenceFrame(this);
      overflow += offset;
      overflow = nsDisplayTransform::TransformRect(overflow, this, offset);

      dirtyRect += offset;

      if (dirtyRect.Intersects(overflow)) {
        // If they intersect, we take our whole overflow rect. We could instead take the intersection
        // and then reverse transform it but I doubt this extra work is worthwhile.
        dirtyRect = GetVisualOverflowRectRelativeToSelf();
      } else {
        dirtyRect.SetEmpty();
      }
      if (!Preserves3DChildren() && !dirtyRect.Intersects(GetVisualOverflowRectRelativeToSelf())) {
        return;
      }
    }
    inTransform = true;
  }

  bool useOpacity = HasOpacity() && !nsSVGUtils::CanOptimizeOpacity(this);
  bool usingSVGEffects = nsSVGIntegrationUtils::UsingEffectsForFrame(this);

  DisplayListClipState::AutoSaveRestore clipState(aBuilder);

  if (isTransformed || useOpacity || usingSVGEffects) {
    // We don't need to pass ancestor clipping down to our children;
    // everything goes inside a display item's child list, and the display
    // item itself will be clipped.
    // For transforms we also need to clear ancestor clipping because it's
    // relative to the wrong display item reference frame anyway.
    clipState.Clear();
  }

  nsDisplayListCollection set;
  {    
    nsDisplayListBuilder::AutoBuildingDisplayList rootSetter(aBuilder, true);
    DisplayListClipState::AutoSaveRestore nestedClipState(aBuilder);
    nsDisplayListBuilder::AutoInTransformSetter
      inTransformSetter(aBuilder, inTransform);

    if (usingSVGEffects) {
      dirtyRect =
        nsSVGIntegrationUtils::GetRequiredSourceForInvalidArea(this, dirtyRect);
    }

    nsRect clipPropClip;
    if (ApplyClipPropClipping(aBuilder, this, disp, &clipPropClip,
                              nestedClipState)) {
      dirtyRect.IntersectRect(dirtyRect, clipPropClip);
    }

    MarkAbsoluteFramesForDisplayList(aBuilder, dirtyRect);

    // Preserve3DChildren() also guarantees that applyAbsPosClipping and usingSVGEffects are false
    // We only modify the preserve-3d rect if we are the top of a preserve-3d heirarchy
    if (Preserves3DChildren()) {
      aBuilder->MarkPreserve3DFramesForDisplayList(this, aDirtyRect);
    }

    BuildDisplayList(aBuilder, dirtyRect, set);
  }

  if (aBuilder->IsBackgroundOnly()) {
    set.BlockBorderBackgrounds()->DeleteAll();
    set.Floats()->DeleteAll();
    set.Content()->DeleteAll();
    set.PositionedDescendants()->DeleteAll();
    set.Outlines()->DeleteAll();
  }
  
  // This z-order sort also sorts secondarily by content order. We need to do
  // this so that boxes produced by the same element are placed together
  // in the sort. Consider a position:relative inline element that breaks
  // across lines and has absolutely positioned children; all the abs-pos
  // children should be z-ordered after all the boxes for the position:relative
  // element itself.
  set.PositionedDescendants()->SortByZOrder(aBuilder, GetContent());
  
  nsDisplayList resultList;
  // Now follow the rules of http://www.w3.org/TR/CSS21/zindex.html
  // 1,2: backgrounds and borders
  resultList.AppendToTop(set.BorderBackground());
  // 3: negative z-index children.
  for (;;) {
    nsDisplayItem* item = set.PositionedDescendants()->GetBottom();
    if (item) {
      nsIFrame* f = item->GetUnderlyingFrame();
      NS_ASSERTION(f, "After sorting, every item in the list should have an underlying frame");
      if (nsLayoutUtils::GetZIndex(f) < 0) {
        set.PositionedDescendants()->RemoveBottom();
        resultList.AppendToTop(item);
        continue;
      }
    }
    break;
  }
  // 4: block backgrounds
  resultList.AppendToTop(set.BlockBorderBackgrounds());
  // 5: floats
  resultList.AppendToTop(set.Floats());
  // 7: general content
  resultList.AppendToTop(set.Content());
  // 7.5: outlines, in content tree order. We need to sort by content order
  // because an element with outline that breaks and has children with outline
  // might have placed child outline items between its own outline items.
  // The element's outline items need to all come before any child outline
  // items.
  nsIContent* content = GetContent();
  if (!content) {
    content = PresContext()->Document()->GetRootElement();
  }
  if (content) {
    set.Outlines()->SortByContentOrder(aBuilder, content);
  }
#ifdef DEBUG
  DisplayDebugBorders(aBuilder, this, set);
#endif
  resultList.AppendToTop(set.Outlines());
  // 8, 9: non-negative z-index children
  resultList.AppendToTop(set.PositionedDescendants());

  if (!isTransformed) {
    // Restore saved clip state now so that any display items we create below
    // are clipped properly.
    clipState.Restore();
  }

  /* If there are any SVG effects, wrap the list up in an SVG effects item
   * (which also handles CSS group opacity). Note that we create an SVG effects
   * item even if resultList is empty, since a filter can produce graphical
   * output even if the element being filtered wouldn't otherwise do so.
   */
  if (usingSVGEffects) {
    /* List now emptied, so add the new list to the top. */
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplaySVGEffects(aBuilder, this, &resultList));
  }
  /* Else, if the list is non-empty and there is CSS group opacity without SVG
   * effects, wrap it up in an opacity item.
   */
  else if (useOpacity && !resultList.IsEmpty()) {
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplayOpacity(aBuilder, this, &resultList));
  }

  /* If we're going to apply a transformation and don't have preserve-3d set, wrap 
   * everything in an nsDisplayTransform. If there's nothing in the list, don't add 
   * anything.
   *
   * For the preserve-3d case we want to individually wrap every child in the list with
   * a separate nsDisplayTransform instead. When the child is already an nsDisplayTransform,
   * we can skip this step, as the computed transform will already include our own.
   *
   * We also traverse into sublists created by nsDisplayWrapList or nsDisplayOpacity, so that
   * we find all the correct children.
   */
  if (isTransformed && !resultList.IsEmpty()) {
    // Restore clip state now so nsDisplayTransform is clipped properly.
    clipState.Restore();

    if (Preserves3DChildren()) {
      WrapPreserve3DList(this, aBuilder, &resultList);
    } else {
      resultList.AppendNewToTop(
        new (aBuilder) nsDisplayTransform(aBuilder, this, &resultList));
    }
  }

  aList->AppendToTop(&resultList);
}

static bool
IsRootScrollFrameActive(nsIPresShell* aPresShell)
{
  nsIScrollableFrame* sf = aPresShell->GetRootScrollFrameAsScrollable();
  return sf && sf->IsScrollingActive();
}

static nsDisplayItem*
WrapInWrapList(nsDisplayListBuilder* aBuilder,
               nsIFrame* aFrame, nsDisplayList* aList)
{
  nsDisplayItem* item = aList->GetBottom();
  if (!item || item->GetAbove() || item->GetUnderlyingFrame() != aFrame) {
    return new (aBuilder) nsDisplayWrapList(aBuilder, aFrame, aList);
  }
  aList->RemoveBottom();
  return item;
}

void
nsIFrame::BuildDisplayListForChild(nsDisplayListBuilder*   aBuilder,
                                   nsIFrame*               aChild,
                                   const nsRect&           aDirtyRect,
                                   const nsDisplayListSet& aLists,
                                   uint32_t                aFlags) {
  // If painting is restricted to just the background of the top level frame,
  // then we have nothing to do here.
  if (aBuilder->IsBackgroundOnly())
    return;

  nsIFrame* child = aChild;
  if (child->GetStateBits() & NS_FRAME_TOO_DEEP_IN_FRAME_TREE)
    return;
  
  bool isSVG = (child->GetStateBits() & NS_FRAME_SVG_LAYOUT);

  // true if this is a real or pseudo stacking context
  bool pseudoStackingContext =
    (aFlags & DISPLAY_CHILD_FORCE_PSEUDO_STACKING_CONTEXT) != 0;
  if (!isSVG &&
      (aFlags & DISPLAY_CHILD_INLINE) &&
      !child->IsFrameOfType(eLineParticipant)) {
    // child is a non-inline frame in an inline context, i.e.,
    // it acts like inline-block or inline-table. Therefore it is a
    // pseudo-stacking-context.
    pseudoStackingContext = true;
  }

  // dirty rect in child-relative coordinates
  nsRect dirty = aDirtyRect - child->GetOffsetTo(this);

  nsIAtom* childType = child->GetType();
  nsDisplayListBuilder::OutOfFlowDisplayData* savedOutOfFlowData = nullptr;
  if (childType == nsGkAtoms::placeholderFrame) {
    nsPlaceholderFrame* placeholder = static_cast<nsPlaceholderFrame*>(child);
    child = placeholder->GetOutOfFlowFrame();
    NS_ASSERTION(child, "No out of flow frame?");
    // If 'child' is a pushed float then it's owned by a block that's not an
    // ancestor of the placeholder, and it will be painted by that block and
    // should not be painted through the placeholder.
    if (!child || nsLayoutUtils::IsPopup(child) ||
        (child->GetStateBits() & NS_FRAME_IS_PUSHED_FLOAT))
      return;
    // Make sure that any attempt to use childType below is disappointed. We
    // could call GetType again but since we don't currently need it, let's
    // avoid the virtual call.
    childType = nullptr;
    // Recheck NS_FRAME_TOO_DEEP_IN_FRAME_TREE
    if (child->GetStateBits() & NS_FRAME_TOO_DEEP_IN_FRAME_TREE)
      return;
    savedOutOfFlowData = static_cast<nsDisplayListBuilder::OutOfFlowDisplayData*>
      (child->Properties().Get(nsDisplayListBuilder::OutOfFlowDisplayDataProperty()));
    if (savedOutOfFlowData) {
      dirty = savedOutOfFlowData->mDirtyRect;
    } else {
      // The out-of-flow frame did not intersect the dirty area. We may still
      // need to traverse into it, since it may contain placeholders we need
      // to enter to reach other out-of-flow frames that are visible.
      dirty.SetEmpty();
    }
    pseudoStackingContext = true;
  }
  if (child->Preserves3D()) {
    nsRect* savedDirty = static_cast<nsRect*>
      (child->Properties().Get(nsDisplayListBuilder::Preserve3DDirtyRectProperty()));
    if (savedDirty) {
      dirty = *savedDirty;
    } else {
      dirty.SetEmpty();
    }
  }

  NS_ASSERTION(childType != nsGkAtoms::placeholderFrame,
               "Should have dealt with placeholders already");
  if (aBuilder->GetSelectedFramesOnly() &&
      child->IsLeaf() &&
      !aChild->IsSelected()) {
    return;
  }

  if (aBuilder->GetIncludeAllOutOfFlows() &&
      (child->GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
    dirty = child->GetVisualOverflowRect();
  } else if (!(child->GetStateBits() & NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO)) {
    // No need to descend into child to catch placeholders for visible
    // positioned stuff. So see if we can short-circuit frame traversal here.

    // We can stop if child's frame subtree's intersection with the
    // dirty area is empty.
    // If the child is a scrollframe that we want to ignore, then we need
    // to descend into it because its scrolled child may intersect the dirty
    // area even if the scrollframe itself doesn't.
    if (child != aBuilder->GetIgnoreScrollFrame()) {
      nsRect childDirty;
      if (!childDirty.IntersectRect(dirty, child->GetVisualOverflowRect()))
        return;
      // Usually we could set dirty to childDirty now but there's no
      // benefit, and it can be confusing. It can especially confuse
      // situations where we're going to ignore a scrollframe's clipping;
      // we wouldn't want to clip the dirty area to the scrollframe's
      // bounds in that case.
    }
  }

  // XXX need to have inline-block and inline-table set pseudoStackingContext
  
  const nsStyleDisplay* ourDisp = StyleDisplay();
  // REVIEW: Taken from nsBoxFrame::Paint
  // Don't paint our children if the theme object is a leaf.
  if (IsThemed(ourDisp) &&
      !PresContext()->GetTheme()->WidgetIsContainer(ourDisp->mAppearance))
    return;

  // Child is composited if it's transformed, partially transparent, or has
  // SVG effects.
  const nsStyleDisplay* disp = child->StyleDisplay();
  const nsStylePosition* pos = child->StylePosition();
  bool isVisuallyAtomic = child->HasOpacity()
    || child->IsTransformed()
    || nsSVGIntegrationUtils::UsingEffectsForFrame(child);

  bool isPositioned = disp->IsPositioned(child);
  bool isStackingContext =
    (isPositioned && pos->mZIndex.GetUnit() == eStyleUnit_Integer) ||
     isVisuallyAtomic || (aFlags & DISPLAY_CHILD_FORCE_STACKING_CONTEXT);

  if (isVisuallyAtomic || isPositioned || (!isSVG && disp->IsFloating(child)) ||
      ((disp->mClipFlags & NS_STYLE_CLIP_RECT) &&
       IsSVGContentWithCSSClip(child)) ||
      (aFlags & DISPLAY_CHILD_FORCE_STACKING_CONTEXT)) {
    // If you change this, also change IsPseudoStackingContextFromStyle()
    pseudoStackingContext = true;
  }
  NS_ASSERTION(!isStackingContext || pseudoStackingContext,
               "Stacking contexts must also be pseudo-stacking-contexts");

  // This controls later whether we build an nsDisplayWrapList or an
  // nsDisplayFixedPosition. We check if we're already building a fixed-pos
  // item and disallow nesting, to prevent the situation of bug #769541
  // occurring.
  // Don't build an nsDisplayFixedPosition if our root scroll frame is not
  // active, that's pointless and the extra layer(s) created may be wasteful.
  bool buildFixedPositionItem = disp->mPosition == NS_STYLE_POSITION_FIXED &&
    !child->GetParent()->GetParent() && !aBuilder->IsInFixedPosition() &&
    IsRootScrollFrameActive(PresContext()->PresShell()) && !isSVG;

  nsDisplayListBuilder::AutoBuildingDisplayList
    buildingForChild(aBuilder, child, pseudoStackingContext, buildFixedPositionItem);
  DisplayListClipState::AutoClipMultiple clipState(aBuilder);

  if (savedOutOfFlowData) {
    clipState.SetClipForContainingBlockDescendants(
      savedOutOfFlowData->mContainingBlockClip);
  }

  // Setup clipping for the parent's overflow:-moz-hidden-unscrollable,
  // or overflow:hidden on elements that don't support scrolling (and therefore
  // don't create nsHTML/XULScrollFrame). This clipping needs to not clip
  // anything directly rendered by the parent, only the rendering of its
  // children.
  // Don't use overflowClip to restrict the dirty rect, since some of the
  // descendants may not be clipped by it. Even if we end up with unnecessary
  // display items, they'll be pruned during ComputeVisibility.
  nsIFrame* parent = child->GetParent();
  const nsStyleDisplay* parentDisp =
    parent == this ? ourDisp : parent->StyleDisplay();
  ApplyOverflowClipping(aBuilder, parent, parentDisp, clipState);

  nsDisplayList list;
  nsDisplayList extraPositionedDescendants;
  if (isStackingContext) {
    // True stacking context.
    // For stacking contexts, BuildDisplayListForStackingContext handles
    // clipping and MarkAbsoluteFramesForDisplayList.
    child->BuildDisplayListForStackingContext(aBuilder, dirty, &list);
    aBuilder->DisplayCaret(child, dirty, &list);
  } else {
    nsRect clipRect;
    if (ApplyClipPropClipping(aBuilder, child, disp, &clipRect, clipState)) {
      // clipRect is in builder-reference-frame coordinates,
      // dirty/clippedDirtyRect are in child coordinates
      dirty.IntersectRect(dirty, clipRect);
    }

    child->MarkAbsoluteFramesForDisplayList(aBuilder, dirty);

    if (!pseudoStackingContext) {
      // THIS IS THE COMMON CASE.
      // Not a pseudo or real stacking context. Do the simple thing and
      // return early.
      child->BuildDisplayList(aBuilder, dirty, aLists);
      aBuilder->DisplayCaret(child, dirty, aLists.Content());
#ifdef DEBUG
      DisplayDebugBorders(aBuilder, child, aLists);
#endif
      return;
    }

    // A pseudo-stacking context (e.g., a positioned element with z-index auto).
    // We allow positioned descendants of the child to escape to our parent
    // stacking context's positioned descendant list, because they might be
    // z-index:non-auto
    nsDisplayListCollection pseudoStack;
    child->BuildDisplayList(aBuilder, dirty, pseudoStack);
    aBuilder->DisplayCaret(child, dirty, pseudoStack.Content());

    list.AppendToTop(pseudoStack.BorderBackground());
    list.AppendToTop(pseudoStack.BlockBorderBackgrounds());
    list.AppendToTop(pseudoStack.Floats());
    list.AppendToTop(pseudoStack.Content());
    list.AppendToTop(pseudoStack.Outlines());
    extraPositionedDescendants.AppendToTop(pseudoStack.PositionedDescendants());
#ifdef DEBUG
    DisplayDebugBorders(aBuilder, child, aLists);
#endif
  }
    
  // Clear clip rect for the construction of the items below. Since we're
  // clipping all their contents, they themselves don't need to be clipped.
  clipState.Clear();

  if (isPositioned || isVisuallyAtomic ||
      (aFlags & DISPLAY_CHILD_FORCE_STACKING_CONTEXT)) {
    // Genuine stacking contexts, and positioned pseudo-stacking-contexts,
    // go in this level.
    if (!list.IsEmpty()) {
      // Make sure the root of a fixed position frame sub-tree gets the
      // correct displaylist item type.
      nsDisplayItem* item;
      if (buildFixedPositionItem) {
        item = new (aBuilder) nsDisplayFixedPosition(aBuilder, child, child, &list);
      } else {
        item = WrapInWrapList(aBuilder, child, &list);
      }
      if (isSVG) {
        aLists.Content()->AppendNewToTop(item);
      } else {
        aLists.PositionedDescendants()->AppendNewToTop(item);
      }

      // Make sure that extra positioned descendants don't escape having
      // their fixed-position metadata applied to them.
      if (buildFixedPositionItem) {
        while (!extraPositionedDescendants.IsEmpty()) {
          item = extraPositionedDescendants.RemoveBottom();
          nsDisplayList fixedPosDescendantList;
          fixedPosDescendantList.AppendToTop(item);
          aLists.PositionedDescendants()->AppendNewToTop(
              new (aBuilder) nsDisplayFixedPosition(aBuilder, item->GetUnderlyingFrame(),
                                                    child, &fixedPosDescendantList));
        }
      }
    }
  } else if (!isSVG && disp->IsFloating(child)) {
    if (!list.IsEmpty()) {
      aLists.Floats()->AppendNewToTop(WrapInWrapList(aBuilder, child, &list));
    }
  } else {
    aLists.Content()->AppendToTop(&list);
  }
  // We delay placing the positioned descendants of positioned frames to here,
  // because in the absence of z-index this is the correct order for them.
  // This doesn't affect correctness because the positioned descendants list
  // is sorted by z-order and content in BuildDisplayListForStackingContext,
  // but it means that sort routine needs to do less work.
  aLists.PositionedDescendants()->AppendToTop(&extraPositionedDescendants);
}

void
nsIFrame::MarkAbsoluteFramesForDisplayList(nsDisplayListBuilder* aBuilder,
                                           const nsRect& aDirtyRect)
{
  if (IsAbsoluteContainer()) {
    aBuilder->MarkFramesForDisplayList(this, GetAbsoluteContainingBlock()->GetChildList(), aDirtyRect);
  }
}

NS_IMETHODIMP  
nsFrame::GetContentForEvent(nsEvent* aEvent,
                            nsIContent** aContent)
{
  nsIFrame* f = nsLayoutUtils::GetNonGeneratedAncestor(this);
  *aContent = f->GetContent();
  NS_IF_ADDREF(*aContent);
  return NS_OK;
}

void
nsFrame::FireDOMEvent(const nsAString& aDOMEventName, nsIContent *aContent)
{
  nsIContent* target = aContent ? aContent : mContent;

  if (target) {
    nsRefPtr<nsAsyncDOMEvent> event =
      new nsAsyncDOMEvent(target, aDOMEventName, true, false);
    if (NS_FAILED(event->PostDOMEvent()))
      NS_WARNING("Failed to dispatch nsAsyncDOMEvent");
  }
}

NS_IMETHODIMP
nsFrame::HandleEvent(nsPresContext* aPresContext, 
                     nsGUIEvent*     aEvent,
                     nsEventStatus*  aEventStatus)
{

  if (aEvent->message == NS_MOUSE_MOVE) {
    return HandleDrag(aPresContext, aEvent, aEventStatus);
  }

  if ((aEvent->eventStructType == NS_MOUSE_EVENT &&
      static_cast<nsMouseEvent*>(aEvent)->button == nsMouseEvent::eLeftButton) ||
      aEvent->eventStructType == NS_TOUCH_EVENT) {
    if (aEvent->message == NS_MOUSE_BUTTON_DOWN || aEvent->message == NS_TOUCH_START) {
      HandlePress(aPresContext, aEvent, aEventStatus);
    } else if (aEvent->message == NS_MOUSE_BUTTON_UP || aEvent->message == NS_TOUCH_END) {
      HandleRelease(aPresContext, aEvent, aEventStatus);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::GetDataForTableSelection(const nsFrameSelection *aFrameSelection,
                                  nsIPresShell *aPresShell, nsMouseEvent *aMouseEvent, 
                                  nsIContent **aParentContent, int32_t *aContentOffset, int32_t *aTarget)
{
  if (!aFrameSelection || !aPresShell || !aMouseEvent || !aParentContent || !aContentOffset || !aTarget)
    return NS_ERROR_NULL_POINTER;

  *aParentContent = nullptr;
  *aContentOffset = 0;
  *aTarget = 0;

  int16_t displaySelection = aPresShell->GetSelectionFlags();

  bool selectingTableCells = aFrameSelection->GetTableCellSelection();

  // DISPLAY_ALL means we're in an editor.
  // If already in cell selection mode, 
  //  continue selecting with mouse drag or end on mouse up,
  //  or when using shift key to extend block of cells
  //  (Mouse down does normal selection unless Ctrl/Cmd is pressed)
  bool doTableSelection =
     displaySelection == nsISelectionDisplay::DISPLAY_ALL && selectingTableCells &&
     (aMouseEvent->message == NS_MOUSE_MOVE ||
      (aMouseEvent->message == NS_MOUSE_BUTTON_UP &&
       aMouseEvent->button == nsMouseEvent::eLeftButton) ||
      aMouseEvent->IsShift());

  if (!doTableSelection)
  {  
    // In Browser, special 'table selection' key must be pressed for table selection
    // or when just Shift is pressed and we're already in table/cell selection mode
#ifdef XP_MACOSX
    doTableSelection = aMouseEvent->IsMeta() || (aMouseEvent->IsShift() && selectingTableCells);
#else
    doTableSelection = aMouseEvent->IsControl() || (aMouseEvent->IsShift() && selectingTableCells);
#endif
  }
  if (!doTableSelection) 
    return NS_OK;

  // Get the cell frame or table frame (or parent) of the current content node
  nsIFrame *frame = this;
  bool foundCell = false;
  bool foundTable = false;

  // Get the limiting node to stop parent frame search
  nsIContent* limiter = aFrameSelection->GetLimiter();

  // If our content node is an ancestor of the limiting node,
  // we should stop the search right now.
  if (limiter && nsContentUtils::ContentIsDescendantOf(limiter, GetContent()))
    return NS_OK;

  //We don't initiate row/col selection from here now,
  //  but we may in future
  //bool selectColumn = false;
  //bool selectRow = false;
  
  while (frame)
  {
    // Check for a table cell by querying to a known CellFrame interface
    nsITableCellLayout *cellElement = do_QueryFrame(frame);
    if (cellElement)
    {
      foundCell = true;
      //TODO: If we want to use proximity to top or left border
      //      for row and column selection, this is the place to do it
      break;
    }
    else
    {
      // If not a cell, check for table
      // This will happen when starting frame is the table or child of a table,
      //  such as a row (we were inbetween cells or in table border)
      nsTableOuterFrame *tableFrame = do_QueryFrame(frame);
      if (tableFrame)
      {
        foundTable = true;
        //TODO: How can we select row when along left table edge
        //  or select column when along top edge?
        break;
      } else {
        frame = frame->GetParent();
        // Stop if we have hit the selection's limiting content node
        if (frame && frame->GetContent() == limiter)
          break;
      }
    }
  }
  // We aren't in a cell or table
  if (!foundCell && !foundTable) return NS_OK;

  nsIContent* tableOrCellContent = frame->GetContent();
  if (!tableOrCellContent) return NS_ERROR_FAILURE;

  nsCOMPtr<nsIContent> parentContent = tableOrCellContent->GetParent();
  if (!parentContent) return NS_ERROR_FAILURE;

  int32_t offset = parentContent->IndexOf(tableOrCellContent);
  // Not likely?
  if (offset < 0) return NS_ERROR_FAILURE;

  // Everything is OK -- set the return values
  *aParentContent = parentContent;
  NS_ADDREF(*aParentContent);

  *aContentOffset = offset;

#if 0
  if (selectRow)
    *aTarget = nsISelectionPrivate::TABLESELECTION_ROW;
  else if (selectColumn)
    *aTarget = nsISelectionPrivate::TABLESELECTION_COLUMN;
  else 
#endif
  if (foundCell)
    *aTarget = nsISelectionPrivate::TABLESELECTION_CELL;
  else if (foundTable)
    *aTarget = nsISelectionPrivate::TABLESELECTION_TABLE;

  return NS_OK;
}

NS_IMETHODIMP
nsFrame::IsSelectable(bool* aSelectable, uint8_t* aSelectStyle) const
{
  if (!aSelectable) //it's ok if aSelectStyle is null
    return NS_ERROR_NULL_POINTER;

  // Like 'visibility', we must check all the parents: if a parent
  // is not selectable, none of its children is selectable.
  //
  // The -moz-all value acts similarly: if a frame has 'user-select:-moz-all',
  // all its children are selectable, even those with 'user-select:none'.
  //
  // As a result, if 'none' and '-moz-all' are not present in the frame hierarchy,
  // aSelectStyle returns the first style that is not AUTO. If these values
  // are present in the frame hierarchy, aSelectStyle returns the style of the
  // topmost parent that has either 'none' or '-moz-all'.
  //
  // For instance, if the frame hierarchy is:
  //    AUTO     -> _MOZ_ALL -> NONE -> TEXT,     the returned value is _MOZ_ALL
  //    TEXT     -> NONE     -> AUTO -> _MOZ_ALL, the returned value is TEXT
  //    _MOZ_ALL -> TEXT     -> AUTO -> AUTO,     the returned value is _MOZ_ALL
  //    AUTO     -> CELL     -> TEXT -> AUTO,     the returned value is TEXT
  //
  uint8_t selectStyle  = NS_STYLE_USER_SELECT_AUTO;
  nsIFrame* frame      = (nsIFrame*)this;

  while (frame) {
    const nsStyleUIReset* userinterface = frame->StyleUIReset();
    switch (userinterface->mUserSelect) {
      case NS_STYLE_USER_SELECT_ALL:
      case NS_STYLE_USER_SELECT_MOZ_ALL:
        // override the previous values
        selectStyle = userinterface->mUserSelect;
        break;
      default:
        // otherwise return the first value which is not 'auto'
        if (selectStyle == NS_STYLE_USER_SELECT_AUTO) {
          selectStyle = userinterface->mUserSelect;
        }
        break;
    }
    frame = frame->GetParent();
  }

  // convert internal values to standard values
  if (selectStyle == NS_STYLE_USER_SELECT_AUTO)
    selectStyle = NS_STYLE_USER_SELECT_TEXT;
  else
  if (selectStyle == NS_STYLE_USER_SELECT_MOZ_ALL)
    selectStyle = NS_STYLE_USER_SELECT_ALL;

  // return stuff
  if (aSelectStyle)
    *aSelectStyle = selectStyle;
  if (mState & NS_FRAME_GENERATED_CONTENT)
    *aSelectable = false;
  else
    *aSelectable = (selectStyle != NS_STYLE_USER_SELECT_NONE);
  return NS_OK;
}

/**
  * Handles the Mouse Press Event for the frame
 */
NS_IMETHODIMP
nsFrame::HandlePress(nsPresContext* aPresContext, 
                     nsGUIEvent*     aEvent,
                     nsEventStatus*  aEventStatus)
{
  NS_ENSURE_ARG_POINTER(aEventStatus);
  if (nsEventStatus_eConsumeNoDefault == *aEventStatus) {
    return NS_OK;
  }

  NS_ENSURE_ARG_POINTER(aEvent);
  if (aEvent->eventStructType == NS_TOUCH_EVENT) {
    return NS_OK;
  }

  //We often get out of sync state issues with mousedown events that
  //get interrupted by alerts/dialogs.
  //Check with the ESM to see if we should process this one
  if (!aPresContext->EventStateManager()->EventStatusOK(aEvent)) 
    return NS_OK;

  nsresult rv;
  nsIPresShell *shell = aPresContext->GetPresShell();
  if (!shell)
    return NS_ERROR_FAILURE;

  // if we are in Navigator and the click is in a draggable node, we don't want
  // to start selection because we don't want to interfere with a potential
  // drag of said node and steal all its glory.
  int16_t isEditor = shell->GetSelectionFlags();
  //weaaak. only the editor can display frame selection not just text and images
  isEditor = isEditor == nsISelectionDisplay::DISPLAY_ALL;

  nsInputEvent* keyEvent = (nsInputEvent*)aEvent;
  if (!keyEvent->IsAlt()) {
    
    for (nsIContent* content = mContent; content;
         content = content->GetParent()) {
      if (nsContentUtils::ContentIsDraggable(content) &&
          !content->IsEditable()) {
        // coordinate stuff is the fix for bug #55921
        if ((mRect - GetPosition()).Contains(
               nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this)))
          return NS_OK;
      }
    }
  }

  // check whether style allows selection
  // if not, don't tell selection the mouse event even occurred.  
  bool    selectable;
  uint8_t selectStyle;
  rv = IsSelectable(&selectable, &selectStyle);
  if (NS_FAILED(rv)) return rv;
  
  // check for select: none
  if (!selectable)
    return NS_OK;

  // When implementing NS_STYLE_USER_SELECT_ELEMENT, NS_STYLE_USER_SELECT_ELEMENTS and
  // NS_STYLE_USER_SELECT_TOGGLE, need to change this logic
  bool useFrameSelection = (selectStyle == NS_STYLE_USER_SELECT_TEXT);

  // If the mouse is dragged outside the nearest enclosing scrollable area
  // while making a selection, the area will be scrolled. To do this, capture
  // the mouse on the nearest scrollable frame. If there isn't a scrollable
  // frame, or something else is already capturing the mouse, there's no
  // reason to capture.
  if (!nsIPresShell::GetCapturingContent()) {
    nsIFrame* checkFrame = this;
    nsIScrollableFrame *scrollFrame = nullptr;
    while (checkFrame) {
      scrollFrame = do_QueryFrame(checkFrame);
      if (scrollFrame) {
        nsIPresShell::SetCapturingContent(checkFrame->GetContent(), CAPTURE_IGNOREALLOWED);
        break;
      }
      checkFrame = checkFrame->GetParent();
    }
  }

  // XXX This is screwy; it really should use the selection frame, not the
  // event frame
  const nsFrameSelection* frameselection = nullptr;
  if (useFrameSelection)
    frameselection = GetConstFrameSelection();
  else
    frameselection = shell->ConstFrameSelection();

  if (!frameselection || frameselection->GetDisplaySelection() == nsISelectionController::SELECTION_OFF)
    return NS_OK;//nothing to do we cannot affect selection from here

  nsMouseEvent *me = (nsMouseEvent *)aEvent;

#ifdef XP_MACOSX
  if (me->IsControl())
    return NS_OK;//short circuit. hard coded for mac due to time restraints.
  bool control = me->IsMeta();
#else
  bool control = me->IsControl();
#endif

  nsRefPtr<nsFrameSelection> fc = const_cast<nsFrameSelection*>(frameselection);
  if (me->clickCount > 1)
  {
    // These methods aren't const but can't actually delete anything,
    // so no need for nsWeakFrame.
    fc->SetMouseDownState(true);
    fc->SetMouseDoubleDown(true);
    return HandleMultiplePress(aPresContext, aEvent, aEventStatus, control);
  }

  nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this);
  ContentOffsets offsets = GetContentOffsetsFromPoint(pt, SKIP_HIDDEN);

  if (!offsets.content)
    return NS_ERROR_FAILURE;

  // On touchables devices, touch the screen is usually a pan action,
  // so let's reposition the caret if needed but do not select text
  // if the touch did not happen over an editable element.  Otherwise,
  // let the user move the caret by tapping and dragging.
  if (!offsets.content->IsEditable() &&
      Preferences::GetBool("browser.ignoreNativeFrameTextSelection", false)) {
    return fc->HandleClick(offsets.content, offsets.StartOffset(),
                           offsets.EndOffset(), false, false,
                           offsets.associateWithNext);
  }

  // Let Ctrl/Cmd+mouse down do table selection instead of drag initiation
  nsCOMPtr<nsIContent>parentContent;
  int32_t  contentOffset;
  int32_t target;
  rv = GetDataForTableSelection(frameselection, shell, me, getter_AddRefs(parentContent), &contentOffset, &target);
  if (NS_SUCCEEDED(rv) && parentContent)
  {
    fc->SetMouseDownState(true);
    return fc->HandleTableSelection(parentContent, contentOffset, target, me);
  }

  fc->SetDelayedCaretData(0);

  // Check if any part of this frame is selected, and if the
  // user clicked inside the selected region. If so, we delay
  // starting a new selection since the user may be trying to
  // drag the selected region to some other app.

  SelectionDetails *details = 0;
  if (GetContent()->IsSelectionDescendant())
  {
    bool inSelection = false;
    details = frameselection->LookUpSelection(offsets.content, 0,
        offsets.EndOffset(), false);

    //
    // If there are any details, check to see if the user clicked
    // within any selected region of the frame.
    //

    SelectionDetails *curDetail = details;

    while (curDetail)
    {
      //
      // If the user clicked inside a selection, then just
      // return without doing anything. We will handle placing
      // the caret later on when the mouse is released. We ignore
      // the spellcheck, find and url formatting selections.
      //
      if (curDetail->mType != nsISelectionController::SELECTION_SPELLCHECK &&
          curDetail->mType != nsISelectionController::SELECTION_FIND &&
          curDetail->mType != nsISelectionController::SELECTION_URLSECONDARY &&
          curDetail->mStart <= offsets.StartOffset() &&
          offsets.EndOffset() <= curDetail->mEnd)
      {
        inSelection = true;
      }

      SelectionDetails *nextDetail = curDetail->mNext;
      delete curDetail;
      curDetail = nextDetail;
    }

    if (inSelection) {
      fc->SetMouseDownState(false);
      fc->SetDelayedCaretData(me);
      return NS_OK;
    }
  }

  fc->SetMouseDownState(true);

  // Do not touch any nsFrame members after this point without adding
  // weakFrame checks.
  rv = fc->HandleClick(offsets.content, offsets.StartOffset(),
                       offsets.EndOffset(), me->IsShift(), control,
                       offsets.associateWithNext);

  if (NS_FAILED(rv))
    return rv;

  if (offsets.offset != offsets.secondaryOffset)
    fc->MaintainSelection();

  if (isEditor && !me->IsShift() &&
      (offsets.EndOffset() - offsets.StartOffset()) == 1)
  {
    // A single node is selected and we aren't extending an existing
    // selection, which means the user clicked directly on an object (either
    // -moz-user-select: all or a non-text node without children).
    // Therefore, disable selection extension during mouse moves.
    // XXX This is a bit hacky; shouldn't editor be able to deal with this?
    fc->SetMouseDownState(false);
  }

  return rv;
}

/*
 * SelectByTypeAtPoint
 *
 * Search for selectable content at point and attempt to select
 * based on the start and end selection behaviours.
 *
 * @param aPresContext Presentation context
 * @param aPoint Point at which selection will occur. Coordinates
 * should be relaitve to this frame.
 * @param aBeginAmountType, aEndAmountType Selection behavior, see
 * nsIFrame for definitions.
 * @param aSelectFlags Selection flags defined in nsFame.h.
 * @return success or failure at finding suitable content to select.
 */
nsresult
nsFrame::SelectByTypeAtPoint(nsPresContext* aPresContext,
                             const nsPoint& aPoint,
                             nsSelectionAmount aBeginAmountType,
                             nsSelectionAmount aEndAmountType,
                             uint32_t aSelectFlags)
{
  NS_ENSURE_ARG_POINTER(aPresContext);

  // No point in selecting if selection is turned off
  if (DisplaySelection(aPresContext) == nsISelectionController::SELECTION_OFF)
    return NS_OK;

  ContentOffsets offsets = GetContentOffsetsFromPoint(aPoint, SKIP_HIDDEN);
  if (!offsets.content)
    return NS_ERROR_FAILURE;

  int32_t offset;
  const nsFrameSelection* frameSelection =
    PresContext()->GetPresShell()->ConstFrameSelection();
  nsIFrame* theFrame = frameSelection->
    GetFrameForNodeOffset(offsets.content, offsets.offset,
                          nsFrameSelection::HINT(offsets.associateWithNext),
                          &offset);
  if (!theFrame)
    return NS_ERROR_FAILURE;

  nsFrame* frame = static_cast<nsFrame*>(theFrame);
  return frame->PeekBackwardAndForward(aBeginAmountType, aEndAmountType, 
                                       offset, aPresContext,
                                       aBeginAmountType != eSelectWord,
                                       aSelectFlags);
}

/**
  * Multiple Mouse Press -- line or paragraph selection -- for the frame.
  * Wouldn't it be nice if this didn't have to be hardwired into Frame code?
 */
NS_IMETHODIMP
nsFrame::HandleMultiplePress(nsPresContext* aPresContext,
                             nsGUIEvent*    aEvent,
                             nsEventStatus* aEventStatus,
                             bool           aControlHeld)
{
  NS_ENSURE_ARG_POINTER(aEvent);
  NS_ENSURE_ARG_POINTER(aEventStatus);

  if (nsEventStatus_eConsumeNoDefault == *aEventStatus ||
      DisplaySelection(aPresContext) == nsISelectionController::SELECTION_OFF) {
    return NS_OK;
  }

  // Find out whether we're doing line or paragraph selection.
  // If browser.triple_click_selects_paragraph is true, triple-click selects paragraph.
  // Otherwise, triple-click selects line, and quadruple-click selects paragraph
  // (on platforms that support quadruple-click).
  nsSelectionAmount beginAmount, endAmount;
  nsMouseEvent *me = (nsMouseEvent *)aEvent;
  if (!me) return NS_OK;

  if (me->clickCount == 4) {
    beginAmount = endAmount = eSelectParagraph;
  } else if (me->clickCount == 3) {
    if (Preferences::GetBool("browser.triple_click_selects_paragraph")) {
      beginAmount = endAmount = eSelectParagraph;
    } else {
      beginAmount = eSelectBeginLine;
      endAmount = eSelectEndLine;
    }
  } else if (me->clickCount == 2) {
    // We only want inline frames; PeekBackwardAndForward dislikes blocks
    beginAmount = endAmount = eSelectWord;
  } else {
    return NS_OK;
  }

  nsPoint relPoint = nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this);
  return SelectByTypeAtPoint(aPresContext, relPoint, beginAmount, endAmount,
                             (aControlHeld ? SELECT_ACCUMULATE : 0));
}

nsresult
nsFrame::PeekBackwardAndForward(nsSelectionAmount aAmountBack,
                                nsSelectionAmount aAmountForward,
                                int32_t aStartPos,
                                nsPresContext* aPresContext,
                                bool aJumpLines,
                                uint32_t aSelectFlags)
{
  nsIFrame* baseFrame = this;
  int32_t baseOffset = aStartPos;
  nsresult rv;

  if (aAmountBack == eSelectWord) {
    // To avoid selecting the previous word when at start of word,
    // first move one character forward.
    nsPeekOffsetStruct pos(eSelectCharacter,
                           eDirNext,
                           aStartPos,
                           0,
                           aJumpLines,
                           true,  //limit on scrolled views
                           false,
                           false);
    rv = PeekOffset(&pos);
    if (NS_SUCCEEDED(rv)) {
      baseFrame = pos.mResultFrame;
      baseOffset = pos.mContentOffset;
    }
  }

  // Use peek offset one way then the other:
  nsPeekOffsetStruct startpos(aAmountBack,
                              eDirPrevious,
                              baseOffset,
                              0,
                              aJumpLines,
                              true,  //limit on scrolled views
                              false,
                              false);
  rv = baseFrame->PeekOffset(&startpos);
  if (NS_FAILED(rv))
    return rv;

  nsPeekOffsetStruct endpos(aAmountForward,
                            eDirNext,
                            aStartPos,
                            0,
                            aJumpLines,
                            true,  //limit on scrolled views
                            false,
                            false);
  rv = PeekOffset(&endpos);
  if (NS_FAILED(rv))
    return rv;

  // Keep frameSelection alive.
  nsRefPtr<nsFrameSelection> frameSelection = GetFrameSelection();

  rv = frameSelection->HandleClick(startpos.mResultContent,
                                   startpos.mContentOffset, startpos.mContentOffset,
                                   false, (aSelectFlags & SELECT_ACCUMULATE),
                                   nsFrameSelection::HINTRIGHT);
  if (NS_FAILED(rv))
    return rv;

  rv = frameSelection->HandleClick(endpos.mResultContent,
                                   endpos.mContentOffset, endpos.mContentOffset,
                                   true, false,
                                   nsFrameSelection::HINTLEFT);
  if (NS_FAILED(rv))
    return rv;

  // maintain selection
  return frameSelection->MaintainSelection(aAmountBack);
}

NS_IMETHODIMP nsFrame::HandleDrag(nsPresContext* aPresContext, 
                                  nsGUIEvent*     aEvent,
                                  nsEventStatus*  aEventStatus)
{
  MOZ_ASSERT(aEvent->eventStructType == NS_MOUSE_EVENT, "HandleDrag can only handle mouse event");

  bool selectable;
  IsSelectable(&selectable, nullptr);

  // XXX Do we really need to exclude non-selectable content here?
  // GetContentOffsetsFromPoint can handle it just fine, although some
  // other stuff might not like it.
  if (!selectable)
    return NS_OK;
  if (DisplaySelection(aPresContext) == nsISelectionController::SELECTION_OFF) {
    return NS_OK;
  }
  nsIPresShell *presShell = aPresContext->PresShell();

  nsRefPtr<nsFrameSelection> frameselection = GetFrameSelection();
  bool mouseDown = frameselection->GetMouseDownState();
  if (!mouseDown)
    return NS_OK;

  frameselection->StopAutoScrollTimer();

  // Check if we are dragging in a table cell
  nsCOMPtr<nsIContent> parentContent;
  int32_t contentOffset;
  int32_t target;
  nsMouseEvent *me = (nsMouseEvent *)aEvent;
  nsresult result;
  result = GetDataForTableSelection(frameselection, presShell, me,
                                    getter_AddRefs(parentContent),
                                    &contentOffset, &target);      

  nsWeakFrame weakThis = this;
  if (NS_SUCCEEDED(result) && parentContent) {
    frameselection->HandleTableSelection(parentContent, contentOffset, target, me);
  } else {
    nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this);
    frameselection->HandleDrag(this, pt);
  }

  // The frameselection object notifies selection listeners synchronously above
  // which might have killed us.
  if (!weakThis.IsAlive()) {
    return NS_OK;
  }

  // get the nearest scrollframe
  nsIFrame* checkFrame = this;
  nsIScrollableFrame *scrollFrame = nullptr;
  while (checkFrame) {
    scrollFrame = do_QueryFrame(checkFrame);
    if (scrollFrame) {
      break;
    }
    checkFrame = checkFrame->GetParent();
  }

  if (scrollFrame) {
    nsIFrame* capturingFrame = scrollFrame->GetScrolledFrame();
    if (capturingFrame) {
      nsPoint pt =
        nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, capturingFrame);
      frameselection->StartAutoScrollTimer(capturingFrame, pt, 30);
    }
  }

  return NS_OK;
}

/**
 * This static method handles part of the nsFrame::HandleRelease in a way
 * which doesn't rely on the nsFrame object to stay alive.
 */
static nsresult
HandleFrameSelection(nsFrameSelection*         aFrameSelection,
                     nsIFrame::ContentOffsets& aOffsets,
                     bool                      aHandleTableSel,
                     int32_t                   aContentOffsetForTableSel,
                     int32_t                   aTargetForTableSel,
                     nsIContent*               aParentContentForTableSel,
                     nsGUIEvent*               aEvent,
                     nsEventStatus*            aEventStatus)
{
  if (!aFrameSelection) {
    return NS_OK;
  }

  nsresult rv = NS_OK;

  if (nsEventStatus_eConsumeNoDefault != *aEventStatus) {
    if (!aHandleTableSel) {
      if (!aOffsets.content || !aFrameSelection->HasDelayedCaretData()) {
        return NS_ERROR_FAILURE;
      }

      // We are doing this to simulate what we would have done on HandlePress.
      // We didn't do it there to give the user an opportunity to drag
      // the text, but since they didn't drag, we want to place the
      // caret.
      // However, we'll use the mouse position from the release, since:
      //  * it's easier
      //  * that's the normal click position to use (although really, in
      //    the normal case, small movements that don't count as a drag
      //    can do selection)
      aFrameSelection->SetMouseDownState(true);

      rv = aFrameSelection->HandleClick(aOffsets.content,
                                        aOffsets.StartOffset(),
                                        aOffsets.EndOffset(),
                                        aFrameSelection->IsShiftDownInDelayedCaretData(),
                                        false,
                                        aOffsets.associateWithNext);
      if (NS_FAILED(rv)) {
        return rv;
      }
    } else if (aParentContentForTableSel) {
      aFrameSelection->SetMouseDownState(false);
      rv = aFrameSelection->HandleTableSelection(aParentContentForTableSel,
                                                 aContentOffsetForTableSel,
                                                 aTargetForTableSel,
                                                 (nsMouseEvent *)aEvent);
      if (NS_FAILED(rv)) {
        return rv;
      }
    }
    aFrameSelection->SetDelayedCaretData(0);
  }

  aFrameSelection->SetMouseDownState(false);
  aFrameSelection->StopAutoScrollTimer();

  return NS_OK;
}

NS_IMETHODIMP nsFrame::HandleRelease(nsPresContext* aPresContext,
                                     nsGUIEvent*    aEvent,
                                     nsEventStatus* aEventStatus)
{
  if (aEvent->eventStructType != NS_MOUSE_EVENT) {
    return NS_OK;
  }

  nsIFrame* activeFrame = GetActiveSelectionFrame(aPresContext, this);

  nsCOMPtr<nsIContent> captureContent = nsIPresShell::GetCapturingContent();

  // We can unconditionally stop capturing because
  // we should never be capturing when the mouse button is up
  nsIPresShell::SetCapturingContent(nullptr, 0);

  bool selectionOff =
    (DisplaySelection(aPresContext) == nsISelectionController::SELECTION_OFF);

  nsRefPtr<nsFrameSelection> frameselection;
  ContentOffsets offsets;
  nsCOMPtr<nsIContent> parentContent;
  int32_t contentOffsetForTableSel = 0;
  int32_t targetForTableSel = 0;
  bool handleTableSelection = true;

  if (!selectionOff) {
    frameselection = GetFrameSelection();
    if (nsEventStatus_eConsumeNoDefault != *aEventStatus && frameselection) {
      // Check if the frameselection recorded the mouse going down.
      // If not, the user must have clicked in a part of the selection.
      // Place the caret before continuing!

      bool mouseDown = frameselection->GetMouseDownState();

      if (!mouseDown && frameselection->HasDelayedCaretData() &&
          frameselection->GetClickCountInDelayedCaretData() < 2) {
        nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this);
        offsets = GetContentOffsetsFromPoint(pt, SKIP_HIDDEN);
        handleTableSelection = false;
      } else {
        GetDataForTableSelection(frameselection, PresContext()->PresShell(),
                                 (nsMouseEvent *)aEvent,
                                 getter_AddRefs(parentContent),
                                 &contentOffsetForTableSel,
                                 &targetForTableSel);
      }
    }
  }

  // We might be capturing in some other document and the event just happened to
  // trickle down here. Make sure that document's frame selection is notified.
  // Note, this may cause the current nsFrame object to be deleted, bug 336592.
  nsRefPtr<nsFrameSelection> frameSelection;
  if (activeFrame != this &&
      static_cast<nsFrame*>(activeFrame)->DisplaySelection(activeFrame->PresContext())
        != nsISelectionController::SELECTION_OFF) {
      frameSelection = activeFrame->GetFrameSelection();
  }

  // Also check the selection of the capturing content which might be in a
  // different document.
  if (!frameSelection && captureContent) {
    nsIDocument* doc = captureContent->GetCurrentDoc();
    if (doc) {
      nsIPresShell* capturingShell = doc->GetShell();
      if (capturingShell && capturingShell != PresContext()->GetPresShell()) {
        frameSelection = capturingShell->FrameSelection();
      }
    }
  }

  if (frameSelection) {
    frameSelection->SetMouseDownState(false);
    frameSelection->StopAutoScrollTimer();
  }

  // Do not call any methods of the current object after this point!!!
  // The object is perhaps dead!

  return selectionOff
    ? NS_OK
    : HandleFrameSelection(frameselection, offsets, handleTableSelection,
                           contentOffsetForTableSel, targetForTableSel,
                           parentContent, aEvent, aEventStatus);
}

struct NS_STACK_CLASS FrameContentRange {
  FrameContentRange(nsIContent* aContent, int32_t aStart, int32_t aEnd) :
    content(aContent), start(aStart), end(aEnd) { }
  nsCOMPtr<nsIContent> content;
  int32_t start;
  int32_t end;
};

// Retrieve the content offsets of a frame
static FrameContentRange GetRangeForFrame(nsIFrame* aFrame) {
  nsCOMPtr<nsIContent> content, parent;
  content = aFrame->GetContent();
  if (!content) {
    NS_WARNING("Frame has no content");
    return FrameContentRange(nullptr, -1, -1);
  }
  nsIAtom* type = aFrame->GetType();
  if (type == nsGkAtoms::textFrame) {
    int32_t offset, offsetEnd;
    aFrame->GetOffsets(offset, offsetEnd);
    return FrameContentRange(content, offset, offsetEnd);
  }
  if (type == nsGkAtoms::brFrame) {
    parent = content->GetParent();
    int32_t beginOffset = parent->IndexOf(content);
    return FrameContentRange(parent, beginOffset, beginOffset);
  }
  // Loop to deal with anonymous content, which has no index; this loop
  // probably won't run more than twice under normal conditions
  do {
    parent  = content->GetParent();
    if (parent) {
      int32_t beginOffset = parent->IndexOf(content);
      if (beginOffset >= 0)
        return FrameContentRange(parent, beginOffset, beginOffset + 1);
      content = parent;
    }
  } while (parent);

  // The root content node must act differently
  return FrameContentRange(content, 0, content->GetChildCount());
}

// The FrameTarget represents the closest frame to a point that can be selected
// The frame is the frame represented, frameEdge says whether one end of the
// frame is the result (in which case different handling is needed), and
// afterFrame says which end is repersented if frameEdge is true
struct FrameTarget {
  FrameTarget(nsIFrame* aFrame, bool aFrameEdge, bool aAfterFrame,
              bool aEmptyBlock = false) :
    frame(aFrame), frameEdge(aFrameEdge), afterFrame(aAfterFrame),
    emptyBlock(aEmptyBlock) { }
  static FrameTarget Null() {
    return FrameTarget(nullptr, false, false);
  }
  bool IsNull() {
    return !frame;
  }
  nsIFrame* frame;
  bool frameEdge;
  bool afterFrame;
  bool emptyBlock;
};

// See function implementation for information
static FrameTarget GetSelectionClosestFrame(nsIFrame* aFrame, nsPoint aPoint,
                                            uint32_t aFlags);

static bool SelfIsSelectable(nsIFrame* aFrame, uint32_t aFlags)
{
  if ((aFlags & nsIFrame::SKIP_HIDDEN) &&
      !aFrame->StyleVisibility()->IsVisible()) {
    return false;
  }
  return !aFrame->IsGeneratedContentFrame() &&
    aFrame->StyleUIReset()->mUserSelect != NS_STYLE_USER_SELECT_NONE;
}

static bool SelectionDescendToKids(nsIFrame* aFrame) {
  uint8_t style = aFrame->StyleUIReset()->mUserSelect;
  nsIFrame* parent = aFrame->GetParent();
  // If we are only near (not directly over) then don't traverse
  // frames with independent selection (e.g. text and list controls)
  // unless we're already inside such a frame (see bug 268497).  Note that this
  // prevents any of the users of this method from entering form controls.
  // XXX We might want some way to allow using the up-arrow to go into a form
  // control, but the focus didn't work right anyway; it'd probably be enough
  // if the left and right arrows could enter textboxes (which I don't believe
  // they can at the moment)
  return !aFrame->IsGeneratedContentFrame() &&
         style != NS_STYLE_USER_SELECT_ALL  &&
         style != NS_STYLE_USER_SELECT_NONE &&
         ((parent->GetStateBits() & NS_FRAME_INDEPENDENT_SELECTION) ||
          !(aFrame->GetStateBits() & NS_FRAME_INDEPENDENT_SELECTION));
}

static FrameTarget GetSelectionClosestFrameForChild(nsIFrame* aChild,
                                                    nsPoint aPoint,
                                                    uint32_t aFlags)
{
  nsIFrame* parent = aChild->GetParent();
  if (SelectionDescendToKids(aChild)) {
    nsPoint pt = aPoint - aChild->GetOffsetTo(parent);
    return GetSelectionClosestFrame(aChild, pt, aFlags);
  }
  return FrameTarget(aChild, false, false);
}

// When the cursor needs to be at the beginning of a block, it shouldn't be
// before the first child.  A click on a block whose first child is a block
// should put the cursor in the child.  The cursor shouldn't be between the
// blocks, because that's not where it's expected.
// Note that this method is guaranteed to succeed.
static FrameTarget DrillDownToSelectionFrame(nsIFrame* aFrame,
                                             bool aEndFrame, uint32_t aFlags) {
  if (SelectionDescendToKids(aFrame)) {
    nsIFrame* result = nullptr;
    nsIFrame *frame = aFrame->GetFirstPrincipalChild();
    if (!aEndFrame) {
      while (frame && (!SelfIsSelectable(frame, aFlags) ||
                        frame->IsEmpty()))
        frame = frame->GetNextSibling();
      if (frame)
        result = frame;
    } else {
      // Because the frame tree is singly linked, to find the last frame,
      // we have to iterate through all the frames
      // XXX I have a feeling this could be slow for long blocks, although
      //     I can't find any slowdowns
      while (frame) {
        if (!frame->IsEmpty() && SelfIsSelectable(frame, aFlags))
          result = frame;
        frame = frame->GetNextSibling();
      }
    }
    if (result)
      return DrillDownToSelectionFrame(result, aEndFrame, aFlags);
  }
  // If the current frame has no targetable children, target the current frame
  return FrameTarget(aFrame, true, aEndFrame);
}

// This method finds the closest valid FrameTarget on a given line; if there is
// no valid FrameTarget on the line, it returns a null FrameTarget
static FrameTarget GetSelectionClosestFrameForLine(
                      nsBlockFrame* aParent,
                      nsBlockFrame::line_iterator aLine,
                      nsPoint aPoint,
                      uint32_t aFlags)
{
  nsIFrame *frame = aLine->mFirstChild;
  // Account for end of lines (any iterator from the block is valid)
  if (aLine == aParent->end_lines())
    return DrillDownToSelectionFrame(aParent, true, aFlags);
  nsIFrame *closestFromLeft = nullptr, *closestFromRight = nullptr;
  nsRect rect = aLine->mBounds;
  nscoord closestLeft = rect.x, closestRight = rect.XMost();
  for (int32_t n = aLine->GetChildCount(); n;
       --n, frame = frame->GetNextSibling()) {
    if (!SelfIsSelectable(frame, aFlags) || frame->IsEmpty())
      continue;
    nsRect frameRect = frame->GetRect();
    if (aPoint.x >= frameRect.x) {
      if (aPoint.x < frameRect.XMost()) {
        return GetSelectionClosestFrameForChild(frame, aPoint, aFlags);
      }
      if (frameRect.XMost() >= closestLeft) {
        closestFromLeft = frame;
        closestLeft = frameRect.XMost();
      }
    } else {
      if (frameRect.x <= closestRight) {
        closestFromRight = frame;
        closestRight = frameRect.x;
      }
    }
  }
  if (!closestFromLeft && !closestFromRight) {
    // We should only get here if there are no selectable frames on a line
    // XXX Do we need more elaborate handling here?
    return FrameTarget::Null();
  }
  if (closestFromLeft &&
      (!closestFromRight ||
       (abs(aPoint.x - closestLeft) <= abs(aPoint.x - closestRight)))) {
    return GetSelectionClosestFrameForChild(closestFromLeft, aPoint, aFlags);
  }
  return GetSelectionClosestFrameForChild(closestFromRight, aPoint, aFlags);
}

// This method is for the special handling we do for block frames; they're
// special because they represent paragraphs and because they are organized
// into lines, which have bounds that are not stored elsewhere in the
// frame tree.  Returns a null FrameTarget for frames which are not
// blocks or blocks with no lines except editable one.
static FrameTarget GetSelectionClosestFrameForBlock(nsIFrame* aFrame,
                                                    nsPoint aPoint,
                                                    uint32_t aFlags)
{
  nsBlockFrame* bf = nsLayoutUtils::GetAsBlock(aFrame); // used only for QI
  if (!bf)
    return FrameTarget::Null();

  // This code searches for the correct line
  nsBlockFrame::line_iterator firstLine = bf->begin_lines();
  nsBlockFrame::line_iterator end = bf->end_lines();
  if (firstLine == end) {
    nsIContent *blockContent = aFrame->GetContent();
    if (blockContent) {
      // Return with empty flag true.
      return FrameTarget(aFrame, false, false, true);
    }
    return FrameTarget::Null();
  }
  nsBlockFrame::line_iterator curLine = firstLine;
  nsBlockFrame::line_iterator closestLine = end;
  while (curLine != end) {
    // Check to see if our point lies with the line's Y bounds
    nscoord y = aPoint.y - curLine->mBounds.y;
    nscoord height = curLine->mBounds.height;
    if (y >= 0 && y < height) {
      closestLine = curLine;
      break; // We found the line; stop looking
    }
    if (y < 0)
      break;
    ++curLine;
  }

  if (closestLine == end) {
    nsBlockFrame::line_iterator prevLine = curLine.prev();
    nsBlockFrame::line_iterator nextLine = curLine;
    // Avoid empty lines
    while (nextLine != end && nextLine->IsEmpty())
      ++nextLine;
    while (prevLine != end && prevLine->IsEmpty())
      --prevLine;

    // This hidden pref dictates whether a point above or below all lines comes
    // up with a line or the beginning or end of the frame; 0 on Windows,
    // 1 on other platforms by default at the writing of this code
    int32_t dragOutOfFrame =
      Preferences::GetInt("browser.drag_out_of_frame_style");

    if (prevLine == end) {
      if (dragOutOfFrame == 1 || nextLine == end)
        return DrillDownToSelectionFrame(aFrame, false, aFlags);
      closestLine = nextLine;
    } else if (nextLine == end) {
      if (dragOutOfFrame == 1)
        return DrillDownToSelectionFrame(aFrame, true, aFlags);
      closestLine = prevLine;
    } else { // Figure out which line is closer
      if (aPoint.y - prevLine->mBounds.YMost() < nextLine->mBounds.y - aPoint.y)
        closestLine = prevLine;
      else
        closestLine = nextLine;
    }
  }

  do {
    FrameTarget target = GetSelectionClosestFrameForLine(bf, closestLine,
                                                         aPoint, aFlags);
    if (!target.IsNull())
      return target;
    ++closestLine;
  } while (closestLine != end);
  // Fall back to just targeting the last targetable place
  return DrillDownToSelectionFrame(aFrame, true, aFlags);
}

// GetSelectionClosestFrame is the helper function that calculates the closest
// frame to the given point.
// It doesn't completely account for offset styles, so needs to be used in
// restricted environments.
// Cannot handle overlapping frames correctly, so it should receive the output
// of GetFrameForPoint
// Guaranteed to return a valid FrameTarget
static FrameTarget GetSelectionClosestFrame(nsIFrame* aFrame, nsPoint aPoint,
                                            uint32_t aFlags)
{
  {
    // Handle blocks; if the frame isn't a block, the method fails
    FrameTarget target = GetSelectionClosestFrameForBlock(aFrame, aPoint, aFlags);
    if (!target.IsNull())
      return target;
  }

  nsIFrame *kid = aFrame->GetFirstPrincipalChild();

  if (kid) {
    // Go through all the child frames to find the closest one
    nsIFrame::FrameWithDistance closest = { nullptr, nscoord_MAX, nscoord_MAX };
    for (; kid; kid = kid->GetNextSibling()) {
      if (!SelfIsSelectable(kid, aFlags) || kid->IsEmpty())
        continue;

      kid->FindCloserFrameForSelection(aPoint, &closest);
    }
    if (closest.mFrame) {
      if (closest.mFrame->IsSVGText())
        return FrameTarget(closest.mFrame, false, false);
      return GetSelectionClosestFrameForChild(closest.mFrame, aPoint, aFlags);
    }
  }
  return FrameTarget(aFrame, false, false);
}

nsIFrame::ContentOffsets OffsetsForSingleFrame(nsIFrame* aFrame, nsPoint aPoint)
{
  nsIFrame::ContentOffsets offsets;
  FrameContentRange range = GetRangeForFrame(aFrame);
  offsets.content = range.content;
  // If there are continuations (meaning it's not one rectangle), this is the
  // best this function can do
  if (aFrame->GetNextContinuation() || aFrame->GetPrevContinuation()) {
    offsets.offset = range.start;
    offsets.secondaryOffset = range.end;
    offsets.associateWithNext = true;
    return offsets;
  }

  // Figure out whether the offsets should be over, after, or before the frame
  nsRect rect(nsPoint(0, 0), aFrame->GetSize());

  bool isBlock = aFrame->GetDisplay() != NS_STYLE_DISPLAY_INLINE;
  bool isRtl = (aFrame->StyleVisibility()->mDirection == NS_STYLE_DIRECTION_RTL);
  if ((isBlock && rect.y < aPoint.y) ||
      (!isBlock && ((isRtl  && rect.x + rect.width / 2 > aPoint.x) || 
                    (!isRtl && rect.x + rect.width / 2 < aPoint.x)))) {
    offsets.offset = range.end;
    if (rect.Contains(aPoint))
      offsets.secondaryOffset = range.start;
    else
      offsets.secondaryOffset = range.end;
  } else {
    offsets.offset = range.start;
    if (rect.Contains(aPoint))
      offsets.secondaryOffset = range.end;
    else
      offsets.secondaryOffset = range.start;
  }
  offsets.associateWithNext = (offsets.offset == range.start);
  return offsets;
}

static nsIFrame* AdjustFrameForSelectionStyles(nsIFrame* aFrame) {
  nsIFrame* adjustedFrame = aFrame;
  for (nsIFrame* frame = aFrame; frame; frame = frame->GetParent())
  {
    // These are the conditions that make all children not able to handle
    // a cursor.
    if (frame->StyleUIReset()->mUserSelect == NS_STYLE_USER_SELECT_ALL ||
        frame->IsGeneratedContentFrame()) {
      adjustedFrame = frame;
    }
  }
  return adjustedFrame;
}

nsIFrame::ContentOffsets nsIFrame::GetContentOffsetsFromPoint(nsPoint aPoint,
                                                              uint32_t aFlags)
{
  nsIFrame *adjustedFrame;
  if (aFlags & IGNORE_SELECTION_STYLE) {
    adjustedFrame = this;
  }
  else {
    // This section of code deals with special selection styles.  Note that
    // -moz-all exists, even though it doesn't need to be explicitly handled.
    //
    // The offset is forced not to end up in generated content; content offsets
    // cannot represent content outside of the document's content tree.

    adjustedFrame = AdjustFrameForSelectionStyles(this);

    // -moz-user-select: all needs special handling, because clicking on it
    // should lead to the whole frame being selected
    if (adjustedFrame && adjustedFrame->StyleUIReset()->mUserSelect ==
        NS_STYLE_USER_SELECT_ALL) {
      nsPoint adjustedPoint = aPoint + this->GetOffsetTo(adjustedFrame);
      return OffsetsForSingleFrame(adjustedFrame, adjustedPoint);
    }

    // For other cases, try to find a closest frame starting from the parent of
    // the unselectable frame
    if (adjustedFrame != this)
      adjustedFrame = adjustedFrame->GetParent();
  }

  nsPoint adjustedPoint = aPoint + this->GetOffsetTo(adjustedFrame);

  FrameTarget closest =
    GetSelectionClosestFrame(adjustedFrame, adjustedPoint, aFlags);

  if (closest.emptyBlock) {
    ContentOffsets offsets;
    NS_ASSERTION(closest.frame,
                 "closest.frame must not be null when it's empty");
    offsets.content = closest.frame->GetContent();
    offsets.offset = 0;
    offsets.secondaryOffset = 0;
    offsets.associateWithNext = true;
    return offsets;
  }

  // If the correct offset is at one end of a frame, use offset-based
  // calculation method
  if (closest.frameEdge) {
    ContentOffsets offsets;
    FrameContentRange range = GetRangeForFrame(closest.frame);
    offsets.content = range.content;
    if (closest.afterFrame)
      offsets.offset = range.end;
    else
      offsets.offset = range.start;
    offsets.secondaryOffset = offsets.offset;
    offsets.associateWithNext = (offsets.offset == range.start);
    return offsets;
  }

  nsPoint pt;
  if (closest.frame != this) {
    if (closest.frame->IsSVGText()) {
      pt = nsLayoutUtils::TransformAncestorPointToFrame(closest.frame,
                                                        aPoint, this);
    } else {
      pt = aPoint - closest.frame->GetOffsetTo(this);
    }
  } else {
    pt = aPoint;
  }
  return static_cast<nsFrame*>(closest.frame)->CalcContentOffsetsFromFramePoint(pt);

  // XXX should I add some kind of offset standardization?
  // consider <b>xxxxx</b><i>zzzzz</i>; should any click between the last
  // x and first z put the cursor in the same logical position in addition
  // to the same visual position?
}

nsIFrame::ContentOffsets nsFrame::CalcContentOffsetsFromFramePoint(nsPoint aPoint)
{
  return OffsetsForSingleFrame(this, aPoint);
}

NS_IMETHODIMP
nsFrame::GetCursor(const nsPoint& aPoint,
                   nsIFrame::Cursor& aCursor)
{
  FillCursorInformationFromStyle(StyleUserInterface(), aCursor);
  if (NS_STYLE_CURSOR_AUTO == aCursor.mCursor) {
    // If this is editable, I-beam cursor is better for most elements.
    aCursor.mCursor =
      (mContent && mContent->IsEditable()) ? NS_STYLE_CURSOR_TEXT :
                                             NS_STYLE_CURSOR_DEFAULT;
  }


  return NS_OK;
}

// Resize and incremental reflow

/* virtual */ void
nsFrame::MarkIntrinsicWidthsDirty()
{
  // This version is meant only for what used to be box-to-block adaptors.
  // It should not be called by other derived classes.
  if (IsBoxWrapped()) {
    nsBoxLayoutMetrics *metrics = BoxMetrics();

    SizeNeedsRecalc(metrics->mPrefSize);
    SizeNeedsRecalc(metrics->mMinSize);
    SizeNeedsRecalc(metrics->mMaxSize);
    SizeNeedsRecalc(metrics->mBlockPrefSize);
    SizeNeedsRecalc(metrics->mBlockMinSize);
    CoordNeedsRecalc(metrics->mFlex);
    CoordNeedsRecalc(metrics->mAscent);
  }

  if (GetStateBits() & NS_FRAME_FONT_INFLATION_FLOW_ROOT) {
    nsFontInflationData::MarkFontInflationDataTextDirty(this);
  }
}

/* virtual */ nscoord
nsFrame::GetMinWidth(nsRenderingContext *aRenderingContext)
{
  nscoord result = 0;
  DISPLAY_MIN_WIDTH(this, result);
  return result;
}

/* virtual */ nscoord
nsFrame::GetPrefWidth(nsRenderingContext *aRenderingContext)
{
  nscoord result = 0;
  DISPLAY_PREF_WIDTH(this, result);
  return result;
}

/* virtual */ void
nsFrame::AddInlineMinWidth(nsRenderingContext *aRenderingContext,
                           nsIFrame::InlineMinWidthData *aData)
{
  NS_ASSERTION(GetParent(), "Must have a parent if we get here!");
  nsIFrame* parent = GetParent();
  bool canBreak = !CanContinueTextRun() &&
    parent->StyleText()->WhiteSpaceCanWrap(parent);
  
  if (canBreak)
    aData->OptionallyBreak(aRenderingContext);
  aData->trailingWhitespace = 0;
  aData->skipWhitespace = false;
  aData->trailingTextFrame = nullptr;
  aData->currentLine += nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
                            this, nsLayoutUtils::MIN_WIDTH);
  aData->atStartOfLine = false;
  if (canBreak)
    aData->OptionallyBreak(aRenderingContext);
}

/* virtual */ void
nsFrame::AddInlinePrefWidth(nsRenderingContext *aRenderingContext,
                            nsIFrame::InlinePrefWidthData *aData)
{
  aData->trailingWhitespace = 0;
  aData->skipWhitespace = false;
  nscoord myPref = nsLayoutUtils::IntrinsicForContainer(aRenderingContext, 
                       this, nsLayoutUtils::PREF_WIDTH);
  aData->currentLine = NSCoordSaturatingAdd(aData->currentLine, myPref);
}

void
nsIFrame::InlineMinWidthData::ForceBreak(nsRenderingContext *aRenderingContext)
{
  currentLine -= trailingWhitespace;
  prevLines = std::max(prevLines, currentLine);
  currentLine = trailingWhitespace = 0;

  for (uint32_t i = 0, i_end = floats.Length(); i != i_end; ++i) {
    nscoord float_min = floats[i].Width();
    if (float_min > prevLines)
      prevLines = float_min;
  }
  floats.Clear();
  trailingTextFrame = nullptr;
  skipWhitespace = true;
}

void
nsIFrame::InlineMinWidthData::OptionallyBreak(nsRenderingContext *aRenderingContext,
                                              nscoord aHyphenWidth)
{
  trailingTextFrame = nullptr;

  // If we can fit more content into a smaller width by staying on this
  // line (because we're still at a negative offset due to negative
  // text-indent or negative margin), don't break.  Otherwise, do the
  // same as ForceBreak.  it doesn't really matter when we accumulate
  // floats.
  if (currentLine + aHyphenWidth < 0 || atStartOfLine)
    return;
  currentLine += aHyphenWidth;
  ForceBreak(aRenderingContext);
}

void
nsIFrame::InlinePrefWidthData::ForceBreak(nsRenderingContext *aRenderingContext)
{
  if (floats.Length() != 0) {
            // preferred widths accumulated for floats that have already
            // been cleared past
    nscoord floats_done = 0,
            // preferred widths accumulated for floats that have not yet
            // been cleared past
            floats_cur_left = 0,
            floats_cur_right = 0;

    for (uint32_t i = 0, i_end = floats.Length(); i != i_end; ++i) {
      const FloatInfo& floatInfo = floats[i];
      const nsStyleDisplay *floatDisp = floatInfo.Frame()->StyleDisplay();
      if (floatDisp->mBreakType == NS_STYLE_CLEAR_LEFT ||
          floatDisp->mBreakType == NS_STYLE_CLEAR_RIGHT ||
          floatDisp->mBreakType == NS_STYLE_CLEAR_LEFT_AND_RIGHT) {
        nscoord floats_cur = NSCoordSaturatingAdd(floats_cur_left,
                                                  floats_cur_right);
        if (floats_cur > floats_done)
          floats_done = floats_cur;
        if (floatDisp->mBreakType != NS_STYLE_CLEAR_RIGHT)
          floats_cur_left = 0;
        if (floatDisp->mBreakType != NS_STYLE_CLEAR_LEFT)
          floats_cur_right = 0;
      }

      nscoord &floats_cur = floatDisp->mFloats == NS_STYLE_FLOAT_LEFT
                              ? floats_cur_left : floats_cur_right;
      nscoord floatWidth = floatInfo.Width();
      // Negative-width floats don't change the available space so they
      // shouldn't change our intrinsic line width either.
      floats_cur =
        NSCoordSaturatingAdd(floats_cur, std::max(0, floatWidth));
    }

    nscoord floats_cur =
      NSCoordSaturatingAdd(floats_cur_left, floats_cur_right);
    if (floats_cur > floats_done)
      floats_done = floats_cur;

    currentLine = NSCoordSaturatingAdd(currentLine, floats_done);

    floats.Clear();
  }

  currentLine =
    NSCoordSaturatingSubtract(currentLine, trailingWhitespace, nscoord_MAX);
  prevLines = std::max(prevLines, currentLine);
  currentLine = trailingWhitespace = 0;
  skipWhitespace = true;
}

static void
AddCoord(const nsStyleCoord& aStyle,
         nsRenderingContext* aRenderingContext,
         nsIFrame* aFrame,
         nscoord* aCoord, float* aPercent,
         bool aClampNegativeToZero)
{
  switch (aStyle.GetUnit()) {
    case eStyleUnit_Coord: {
      NS_ASSERTION(!aClampNegativeToZero || aStyle.GetCoordValue() >= 0,
                   "unexpected negative value");
      *aCoord += aStyle.GetCoordValue();
      return;
    }
    case eStyleUnit_Percent: {
      NS_ASSERTION(!aClampNegativeToZero || aStyle.GetPercentValue() >= 0.0f,
                   "unexpected negative value");
      *aPercent += aStyle.GetPercentValue();
      return;
    }
    case eStyleUnit_Calc: {
      const nsStyleCoord::Calc *calc = aStyle.GetCalcValue();
      if (aClampNegativeToZero) {
        // This is far from ideal when one is negative and one is positive.
        *aCoord += std::max(calc->mLength, 0);
        *aPercent += std::max(calc->mPercent, 0.0f);
      } else {
        *aCoord += calc->mLength;
        *aPercent += calc->mPercent;
      }
      return;
    }
    default: {
      return;
    }
  }
}

/* virtual */ nsIFrame::IntrinsicWidthOffsetData
nsFrame::IntrinsicWidthOffsets(nsRenderingContext* aRenderingContext)
{
  IntrinsicWidthOffsetData result;

  const nsStyleMargin *styleMargin = StyleMargin();
  AddCoord(styleMargin->mMargin.GetLeft(), aRenderingContext, this,
           &result.hMargin, &result.hPctMargin, false);
  AddCoord(styleMargin->mMargin.GetRight(), aRenderingContext, this,
           &result.hMargin, &result.hPctMargin, false);

  const nsStylePadding *stylePadding = StylePadding();
  AddCoord(stylePadding->mPadding.GetLeft(), aRenderingContext, this,
           &result.hPadding, &result.hPctPadding, true);
  AddCoord(stylePadding->mPadding.GetRight(), aRenderingContext, this,
           &result.hPadding, &result.hPctPadding, true);

  const nsStyleBorder *styleBorder = StyleBorder();
  result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_LEFT);
  result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_RIGHT);

  const nsStyleDisplay *disp = StyleDisplay();
  if (IsThemed(disp)) {
    nsPresContext *presContext = PresContext();

    nsIntMargin border;
    presContext->GetTheme()->GetWidgetBorder(presContext->DeviceContext(),
                                             this, disp->mAppearance,
                                             &border);
    result.hBorder = presContext->DevPixelsToAppUnits(border.LeftRight());

    nsIntMargin padding;
    if (presContext->GetTheme()->GetWidgetPadding(presContext->DeviceContext(),
                                                  this, disp->mAppearance,
                                                  &padding)) {
      result.hPadding = presContext->DevPixelsToAppUnits(padding.LeftRight());
      result.hPctPadding = 0;
    }
  }

  return result;
}

/* virtual */ nsIFrame::IntrinsicSize
nsFrame::GetIntrinsicSize()
{
  return IntrinsicSize(); // default is width/height set to eStyleUnit_None
}

/* virtual */ nsSize
nsFrame::GetIntrinsicRatio()
{
  return nsSize(0, 0);
}

/* virtual */ nsSize
nsFrame::ComputeSize(nsRenderingContext *aRenderingContext,
                     nsSize aCBSize, nscoord aAvailableWidth,
                     nsSize aMargin, nsSize aBorder, nsSize aPadding,
                     uint32_t aFlags)
{
  nsSize result = ComputeAutoSize(aRenderingContext, aCBSize, aAvailableWidth,
                                  aMargin, aBorder, aPadding,
                                  aFlags & eShrinkWrap);
  nsSize boxSizingAdjust(0,0);
  const nsStylePosition *stylePos = StylePosition();

  switch (stylePos->mBoxSizing) {
    case NS_STYLE_BOX_SIZING_BORDER:
      boxSizingAdjust += aBorder;
      // fall through
    case NS_STYLE_BOX_SIZING_PADDING:
      boxSizingAdjust += aPadding;
  }
  nscoord boxSizingToMarginEdgeWidth =
    aMargin.width + aBorder.width + aPadding.width - boxSizingAdjust.width;
  const nsStyleCoord* widthStyleCoord = &(stylePos->mWidth);
  const nsStyleCoord* heightStyleCoord = &(stylePos->mHeight);

  bool isFlexItem = IsFlexItem();
  bool isHorizontalFlexItem = false;
 
#ifdef MOZ_FLEXBOX
  if (isFlexItem) {
    // Flex items use their "flex-basis" property in place of their main-size
    // property (e.g. "width") for sizing purposes, *unless* they have
    // "flex-basis:auto", in which case they use their main-size property after
    // all.
    uint32_t flexDirection = mParent->StylePosition()->mFlexDirection;
    isHorizontalFlexItem =
      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW ||
      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW_REVERSE;

    // NOTE: The logic here should match the similar chunk for determining
    // widthStyleCoord and heightStyleCoord in
    // nsLayoutUtils::ComputeSizeWithIntrinsicDimensions().
    const nsStyleCoord* flexBasis = &(stylePos->mFlexBasis);
    if (flexBasis->GetUnit() != eStyleUnit_Auto) {
      if (isHorizontalFlexItem) {
        widthStyleCoord = flexBasis;
      } else {
        // One caveat for vertical flex items: We don't support enumerated
        // values (e.g. "max-content") for height properties yet. So, if our
        // computed flex-basis is an enumerated value, we'll just behave as if
        // it were "auto", which means "use the main-size property after all"
        // (which is "height", in this case).
        // NOTE: Once we support intrinsic sizing keywords for "height",
        // we should remove this check.
        if (flexBasis->GetUnit() != eStyleUnit_Enumerated) {
          heightStyleCoord = flexBasis;
        }
      }
    }
  }
#endif // MOZ_FLEXBOX

  // Compute width

  if (widthStyleCoord->GetUnit() != eStyleUnit_Auto) {
    result.width =
      nsLayoutUtils::ComputeWidthValue(aRenderingContext, this,
        aCBSize.width, boxSizingAdjust.width, boxSizingToMarginEdgeWidth,
        *widthStyleCoord);
  }

  // Flex items ignore their min & max sizing properties in their
  // flex container's main-axis.  (Those properties get applied later in
  // the flexbox algorithm.)
  if (stylePos->mMaxWidth.GetUnit() != eStyleUnit_None &&
      !(isFlexItem && isHorizontalFlexItem)) {
    nscoord maxWidth =
      nsLayoutUtils::ComputeWidthValue(aRenderingContext, this,
        aCBSize.width, boxSizingAdjust.width, boxSizingToMarginEdgeWidth,
        stylePos->mMaxWidth);
    result.width = std::min(maxWidth, result.width);
  }

  nscoord minWidth;
  if (!(isFlexItem && isHorizontalFlexItem)) {
    minWidth =
      nsLayoutUtils::ComputeWidthValue(aRenderingContext, this,
        aCBSize.width, boxSizingAdjust.width, boxSizingToMarginEdgeWidth,
        stylePos->mMinWidth);
  } else {
    minWidth = 0;
  }
  result.width = std::max(minWidth, result.width);

  // Compute height
  // (but not if we're auto-height or if we recieved the "eUseAutoHeight"
  // flag -- then, we'll just stick with the height that we already calculated
  // in the initial ComputeAutoSize() call.)
  if (!nsLayoutUtils::IsAutoHeight(*heightStyleCoord, aCBSize.height) &&
      !(aFlags & nsIFrame::eUseAutoHeight)) {
    result.height =
      nsLayoutUtils::ComputeHeightValue(aCBSize.height, 
                                        boxSizingAdjust.height,
                                        *heightStyleCoord);
  }

  if (result.height != NS_UNCONSTRAINEDSIZE) {
    if (!nsLayoutUtils::IsAutoHeight(stylePos->mMaxHeight, aCBSize.height) &&
        !(isFlexItem && !isHorizontalFlexItem)) {
      nscoord maxHeight =
        nsLayoutUtils::ComputeHeightValue(aCBSize.height, 
                                          boxSizingAdjust.height,
                                          stylePos->mMaxHeight);
      result.height = std::min(maxHeight, result.height);
    }

    if (!nsLayoutUtils::IsAutoHeight(stylePos->mMinHeight, aCBSize.height) &&
        !(isFlexItem && !isHorizontalFlexItem)) {
      nscoord minHeight =
        nsLayoutUtils::ComputeHeightValue(aCBSize.height, 
                                          boxSizingAdjust.height, 
                                          stylePos->mMinHeight);
      result.height = std::max(minHeight, result.height);
    }
  }

  const nsStyleDisplay *disp = StyleDisplay();
  if (IsThemed(disp)) {
    nsIntSize widget(0, 0);
    bool canOverride = true;
    nsPresContext *presContext = PresContext();
    presContext->GetTheme()->
      GetMinimumWidgetSize(aRenderingContext, this, disp->mAppearance,
                           &widget, &canOverride);

    nsSize size;
    size.width = presContext->DevPixelsToAppUnits(widget.width);
    size.height = presContext->DevPixelsToAppUnits(widget.height);

    // GMWS() returns border-box; we need content-box
    size.width -= aBorder.width + aPadding.width;
    size.height -= aBorder.height + aPadding.height;

    if (size.height > result.height || !canOverride)
      result.height = size.height;
    if (size.width > result.width || !canOverride)
      result.width = size.width;
  }

  result.width = std::max(0, result.width);
  result.height = std::max(0, result.height);

  return result;
}

nsRect
nsIFrame::ComputeTightBounds(gfxContext* aContext) const
{
  return GetVisualOverflowRect();
}

nsRect
nsFrame::ComputeSimpleTightBounds(gfxContext* aContext) const
{
  if (StyleOutline()->GetOutlineStyle() != NS_STYLE_BORDER_STYLE_NONE ||
      StyleBorder()->HasBorder() || !StyleBackground()->IsTransparent() ||
      StyleDisplay()->mAppearance) {
    // Not necessarily tight, due to clipping, negative
    // outline-offset, and lots of other issues, but that's OK
    return GetVisualOverflowRect();
  }

  nsRect r(0, 0, 0, 0);
  ChildListIterator lists(this);
  for (; !lists.IsDone(); lists.Next()) {
    nsFrameList::Enumerator childFrames(lists.CurrentList());
    for (; !childFrames.AtEnd(); childFrames.Next()) {
      nsIFrame* child = childFrames.get();
      r.UnionRect(r, child->ComputeTightBounds(aContext) + child->GetPosition());
    }
  }
  return r;
}

/* virtual */ nsSize
nsFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
                         nsSize aCBSize, nscoord aAvailableWidth,
                         nsSize aMargin, nsSize aBorder, nsSize aPadding,
                         bool aShrinkWrap)
{
  // Use basic shrink-wrapping as a default implementation.
  nsSize result(0xdeadbeef, NS_UNCONSTRAINEDSIZE);

  // don't bother setting it if the result won't be used
  if (StylePosition()->mWidth.GetUnit() == eStyleUnit_Auto) {
    nscoord availBased = aAvailableWidth - aMargin.width - aBorder.width -
                         aPadding.width;
    result.width = ShrinkWidthToFit(aRenderingContext, availBased);
  }
  return result;
}

nscoord
nsFrame::ShrinkWidthToFit(nsRenderingContext *aRenderingContext,
                          nscoord aWidthInCB)
{
  // If we're a container for font size inflation, then shrink
  // wrapping inside of us should not apply font size inflation.
  AutoMaybeDisableFontInflation an(this);

  nscoord result;
  nscoord minWidth = GetMinWidth(aRenderingContext);
  if (minWidth > aWidthInCB) {
    result = minWidth;
  } else {
    nscoord prefWidth = GetPrefWidth(aRenderingContext);
    if (prefWidth > aWidthInCB) {
      result = aWidthInCB;
    } else {
      result = prefWidth;
    }
  }
  return result;
}

NS_IMETHODIMP
nsFrame::WillReflow(nsPresContext* aPresContext)
{
#ifdef DEBUG_dbaron_off
  // bug 81268
  NS_ASSERTION(!(mState & NS_FRAME_IN_REFLOW),
               "nsFrame::WillReflow: frame is already in reflow");
#endif

  NS_FRAME_TRACE_MSG(NS_FRAME_TRACE_CALLS,
                     ("WillReflow: oldState=%x", mState));
  mState |= NS_FRAME_IN_REFLOW;
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::DidReflow(nsPresContext*           aPresContext,
                   const nsHTMLReflowState*  aReflowState,
                   nsDidReflowStatus         aStatus)
{
  NS_FRAME_TRACE_MSG(NS_FRAME_TRACE_CALLS,
                     ("nsFrame::DidReflow: aStatus=%d", static_cast<uint32_t>(aStatus)));

  nsSVGEffects::InvalidateDirectRenderingObservers(this, nsSVGEffects::INVALIDATE_REFLOW);

  if (nsDidReflowStatus::FINISHED == aStatus) {
    mState &= ~(NS_FRAME_IN_REFLOW | NS_FRAME_FIRST_REFLOW | NS_FRAME_IS_DIRTY |
                NS_FRAME_HAS_DIRTY_CHILDREN);
  }

  // Notify the percent height observer if there is a percent height.
  // The observer may be able to initiate another reflow with a computed
  // height. This happens in the case where a table cell has no computed
  // height but can fabricate one when the cell height is known.
  if (aReflowState && aReflowState->mPercentHeightObserver &&
      !GetPrevInFlow()) {
    const nsStyleCoord &height = aReflowState->mStylePosition->mHeight;
    if (height.HasPercent()) {
      aReflowState->mPercentHeightObserver->NotifyPercentHeight(*aReflowState);
    }
  }

  return NS_OK;
}

void
nsFrame::FinishReflowWithAbsoluteFrames(nsPresContext*           aPresContext,
                                        nsHTMLReflowMetrics&     aDesiredSize,
                                        const nsHTMLReflowState& aReflowState,
                                        nsReflowStatus&          aStatus,
                                        bool                     aConstrainHeight)
{
  ReflowAbsoluteFrames(aPresContext, aDesiredSize, aReflowState, aStatus, aConstrainHeight);

  FinishAndStoreOverflow(&aDesiredSize);
}

void
nsFrame::ReflowAbsoluteFrames(nsPresContext*           aPresContext,
                              nsHTMLReflowMetrics&     aDesiredSize,
                              const nsHTMLReflowState& aReflowState,
                              nsReflowStatus&          aStatus,
                              bool                     aConstrainHeight)
{
  if (HasAbsolutelyPositionedChildren()) {
    nsAbsoluteContainingBlock* absoluteContainer = GetAbsoluteContainingBlock();

    // Let the absolutely positioned container reflow any absolutely positioned
    // child frames that need to be reflowed

    // The containing block for the abs pos kids is formed by our padding edge.
    nsMargin computedBorder =
      aReflowState.mComputedBorderPadding - aReflowState.mComputedPadding;
    nscoord containingBlockWidth =
      aDesiredSize.width - computedBorder.LeftRight();
    nscoord containingBlockHeight =
      aDesiredSize.height - computedBorder.TopBottom();

    nsContainerFrame* container = do_QueryFrame(this);
    NS_ASSERTION(container, "Abs-pos children only supported on container frames for now");

    absoluteContainer->Reflow(container, aPresContext, aReflowState, aStatus,
                              containingBlockWidth, containingBlockHeight,
                              aConstrainHeight, true, true, // XXX could be optimized
                              &aDesiredSize.mOverflowAreas);
  }
}

/* virtual */ bool
nsFrame::CanContinueTextRun() const
{
  // By default, a frame will *not* allow a text run to be continued
  // through it.
  return false;
}

NS_IMETHODIMP
nsFrame::Reflow(nsPresContext*          aPresContext,
                nsHTMLReflowMetrics&     aDesiredSize,
                const nsHTMLReflowState& aReflowState,
                nsReflowStatus&          aStatus)
{
  DO_GLOBAL_REFLOW_COUNT("nsFrame");
  aDesiredSize.width = 0;
  aDesiredSize.height = 0;
  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowState, aDesiredSize);
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::CharacterDataChanged(CharacterDataChangeInfo* aInfo)
{
  NS_NOTREACHED("should only be called for text frames");
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::AttributeChanged(int32_t         aNameSpaceID,
                          nsIAtom*        aAttribute,
                          int32_t         aModType)
{
  return NS_OK;
}

// Flow member functions

nsSplittableType
nsFrame::GetSplittableType() const
{
  return NS_FRAME_NOT_SPLITTABLE;
}

nsIFrame* nsFrame::GetPrevContinuation() const
{
  return nullptr;
}

NS_IMETHODIMP nsFrame::SetPrevContinuation(nsIFrame* aPrevContinuation)
{
  // Ignore harmless requests to set it to NULL
  if (aPrevContinuation) {
    NS_ERROR("not splittable");
    return NS_ERROR_NOT_IMPLEMENTED;
  }
  
  return NS_OK;
}

nsIFrame* nsFrame::GetNextContinuation() const
{
  return nullptr;
}

NS_IMETHODIMP nsFrame::SetNextContinuation(nsIFrame*)
{
  NS_ERROR("not splittable");
  return NS_ERROR_NOT_IMPLEMENTED;
}

nsIFrame* nsFrame::GetPrevInFlowVirtual() const
{
  return nullptr;
}

NS_IMETHODIMP nsFrame::SetPrevInFlow(nsIFrame* aPrevInFlow)
{
  // Ignore harmless requests to set it to NULL
  if (aPrevInFlow) {
    NS_ERROR("not splittable");
    return NS_ERROR_NOT_IMPLEMENTED;
  }

  return NS_OK;
}

nsIFrame* nsFrame::GetNextInFlowVirtual() const
{
  return nullptr;
}

NS_IMETHODIMP nsFrame::SetNextInFlow(nsIFrame*)
{
  NS_ERROR("not splittable");
  return NS_ERROR_NOT_IMPLEMENTED;
}

nsIFrame* nsIFrame::GetTailContinuation()
{
  nsIFrame* frame = this;
  while (frame->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER) {
    frame = frame->GetPrevContinuation();
    NS_ASSERTION(frame, "first continuation can't be overflow container");
  }
  for (nsIFrame* next = frame->GetNextContinuation();
       next && !(next->GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER);
       next = frame->GetNextContinuation())  {
    frame = next;
  }
  NS_POSTCONDITION(frame, "illegal state in continuation chain.");
  return frame;
}

NS_DECLARE_FRAME_PROPERTY(ViewProperty, nullptr)

// Associated view object
nsView*
nsIFrame::GetView() const
{
  // Check the frame state bit and see if the frame has a view
  if (!(GetStateBits() & NS_FRAME_HAS_VIEW))
    return nullptr;

  // Check for a property on the frame
  void* value = Properties().Get(ViewProperty());
  NS_ASSERTION(value, "frame state bit was set but frame has no view");
  return static_cast<nsView*>(value);
}

/* virtual */ nsView*
nsIFrame::GetViewExternal() const
{
  return GetView();
}

nsresult
nsIFrame::SetView(nsView* aView)
{
  if (aView) {
    aView->SetFrame(this);

    // Set a property on the frame
    Properties().Set(ViewProperty(), aView);

    // Set the frame state bit that says the frame has a view
    AddStateBits(NS_FRAME_HAS_VIEW);

    // Let all of the ancestors know they have a descendant with a view.
    for (nsIFrame* f = GetParent();
         f && !(f->GetStateBits() & NS_FRAME_HAS_CHILD_WITH_VIEW);
         f = f->GetParent())
      f->AddStateBits(NS_FRAME_HAS_CHILD_WITH_VIEW);
  }

  return NS_OK;
}

nsIFrame* nsIFrame::GetAncestorWithViewExternal() const
{
  return GetAncestorWithView();
}

// Find the first geometric parent that has a view
nsIFrame* nsIFrame::GetAncestorWithView() const
{
  for (nsIFrame* f = mParent; nullptr != f; f = f->GetParent()) {
    if (f->HasView()) {
      return f;
    }
  }
  return nullptr;
}

// virtual
nsPoint nsIFrame::GetOffsetToExternal(const nsIFrame* aOther) const
{
  return GetOffsetTo(aOther);
}

nsPoint nsIFrame::GetOffsetTo(const nsIFrame* aOther) const
{
  NS_PRECONDITION(aOther,
                  "Must have frame for destination coordinate system!");

  NS_ASSERTION(PresContext() == aOther->PresContext(),
               "GetOffsetTo called on frames in different documents");

  nsPoint offset(0, 0);
  const nsIFrame* f;
  for (f = this; f != aOther && f; f = f->GetParent()) {
    offset += f->GetPosition();
  }

  if (f != aOther) {
    // Looks like aOther wasn't an ancestor of |this|.  So now we have
    // the root-frame-relative position of |this| in |offset|.  Convert back
    // to the coordinates of aOther
    while (aOther) {
      offset -= aOther->GetPosition();
      aOther = aOther->GetParent();
    }
  }

  return offset;
}

nsPoint nsIFrame::GetOffsetToCrossDoc(const nsIFrame* aOther) const
{
  return GetOffsetToCrossDoc(aOther, PresContext()->AppUnitsPerDevPixel());
}

nsPoint
nsIFrame::GetOffsetToCrossDoc(const nsIFrame* aOther, const int32_t aAPD) const
{
  NS_PRECONDITION(aOther,
                  "Must have frame for destination coordinate system!");
  NS_ASSERTION(PresContext()->GetRootPresContext() ==
                 aOther->PresContext()->GetRootPresContext(),
               "trying to get the offset between frames in different document "
               "hierarchies?");
  if (PresContext()->GetRootPresContext() !=
        aOther->PresContext()->GetRootPresContext()) {
    // crash right away, we are almost certainly going to crash anyway.
    NS_RUNTIMEABORT("trying to get the offset between frames in different "
                    "document hierarchies?");
  }

  const nsIFrame* root = nullptr;
  // offset will hold the final offset
  // docOffset holds the currently accumulated offset at the current APD, it
  // will be converted and added to offset when the current APD changes.
  nsPoint offset(0, 0), docOffset(0, 0);
  const nsIFrame* f = this;
  int32_t currAPD = PresContext()->AppUnitsPerDevPixel();
  while (f && f != aOther) {
    docOffset += f->GetPosition();
    nsIFrame* parent = f->GetParent();
    if (parent) {
      f = parent;
    } else {
      nsPoint newOffset(0, 0);
      root = f;
      f = nsLayoutUtils::GetCrossDocParentFrame(f, &newOffset);
      int32_t newAPD = f ? f->PresContext()->AppUnitsPerDevPixel() : 0;
      if (!f || newAPD != currAPD) {
        // Convert docOffset to the right APD and add it to offset.
        offset += docOffset.ConvertAppUnits(currAPD, aAPD);
        docOffset.x = docOffset.y = 0;
      }
      currAPD = newAPD;
      docOffset += newOffset;
    }
  }
  if (f == aOther) {
    offset += docOffset.ConvertAppUnits(currAPD, aAPD);
  } else {
    // Looks like aOther wasn't an ancestor of |this|.  So now we have
    // the root-document-relative position of |this| in |offset|. Subtract the
    // root-document-relative position of |aOther| from |offset|.
    // This call won't try to recurse again because root is an ancestor of
    // aOther.
    nsPoint negOffset = aOther->GetOffsetToCrossDoc(root, aAPD);
    offset -= negOffset;
  }

  return offset;
}

// virtual
nsIntRect nsIFrame::GetScreenRectExternal() const
{
  return GetScreenRect();
}

nsIntRect nsIFrame::GetScreenRect() const
{
  return GetScreenRectInAppUnits().ToNearestPixels(PresContext()->AppUnitsPerCSSPixel());
}

// virtual
nsRect nsIFrame::GetScreenRectInAppUnitsExternal() const
{
  return GetScreenRectInAppUnits();
}

nsRect nsIFrame::GetScreenRectInAppUnits() const
{
  nsPresContext* presContext = PresContext();
  nsIFrame* rootFrame =
    presContext->PresShell()->FrameManager()->GetRootFrame();
  nsPoint rootScreenPos(0, 0);
  nsPoint rootFrameOffsetInParent(0, 0);
  nsIFrame* rootFrameParent =
    nsLayoutUtils::GetCrossDocParentFrame(rootFrame, &rootFrameOffsetInParent);
  if (rootFrameParent) {
    nsRect parentScreenRectAppUnits = rootFrameParent->GetScreenRectInAppUnits();
    nsPresContext* parentPresContext = rootFrameParent->PresContext();
    double parentScale = double(presContext->AppUnitsPerDevPixel())/
        parentPresContext->AppUnitsPerDevPixel();
    nsPoint rootPt = parentScreenRectAppUnits.TopLeft() + rootFrameOffsetInParent;
    rootScreenPos.x = NS_round(parentScale*rootPt.x);
    rootScreenPos.y = NS_round(parentScale*rootPt.y);
  } else {
    nsCOMPtr<nsIWidget> rootWidget;
    presContext->PresShell()->GetViewManager()->GetRootWidget(getter_AddRefs(rootWidget));
    if (rootWidget) {
      nsIntPoint rootDevPx = rootWidget->WidgetToScreenOffset();
      rootScreenPos.x = presContext->DevPixelsToAppUnits(rootDevPx.x);
      rootScreenPos.y = presContext->DevPixelsToAppUnits(rootDevPx.y);
    }
  }

  return nsRect(rootScreenPos + GetOffsetTo(rootFrame), GetSize());
}

// Returns the offset from this frame to the closest geometric parent that
// has a view. Also returns the containing view or null in case of error
NS_IMETHODIMP nsFrame::GetOffsetFromView(nsPoint&  aOffset,
                                         nsView** aView) const
{
  NS_PRECONDITION(nullptr != aView, "null OUT parameter pointer");
  nsIFrame* frame = (nsIFrame*)this;

  *aView = nullptr;
  aOffset.MoveTo(0, 0);
  do {
    aOffset += frame->GetPosition();
    frame = frame->GetParent();
  } while (frame && !frame->HasView());
  if (frame)
    *aView = frame->GetView();
  return NS_OK;
}

nsIWidget*
nsIFrame::GetNearestWidget() const
{
  return GetClosestView()->GetNearestWidget(nullptr);
}

nsIWidget*
nsIFrame::GetNearestWidget(nsPoint& aOffset) const
{
  nsPoint offsetToView;
  nsPoint offsetToWidget;
  nsIWidget* widget =
    GetClosestView(&offsetToView)->GetNearestWidget(&offsetToWidget);
  aOffset = offsetToView + offsetToWidget;
  return widget;
}

nsIAtom*
nsFrame::GetType() const
{
  return nullptr;
}

bool
nsIFrame::IsLeaf() const
{
  return true;
}

class LayerActivity {
public:
  LayerActivity(nsIFrame* aFrame) : mFrame(aFrame), mChangeHint(nsChangeHint(0)) {}
  ~LayerActivity();
  nsExpirationState* GetExpirationState() { return &mState; }

  nsIFrame* mFrame;
  nsExpirationState mState;
  // mChangeHint can be some combination of nsChangeHint_UpdateOpacityLayer and
  // nsChangeHint_UpdateTransformLayer (or neither)
  // The presence of those bits indicates whether opacity or transform
  // changes have been detected.
  nsChangeHint mChangeHint;
};

class LayerActivityTracker MOZ_FINAL : public nsExpirationTracker<LayerActivity,4> {
public:
  // 75-100ms is a good timeout period. We use 4 generations of 25ms each.
  enum { GENERATION_MS = 100 };
  LayerActivityTracker()
    : nsExpirationTracker<LayerActivity,4>(GENERATION_MS) {}
  ~LayerActivityTracker() {
    AgeAllGenerations();
  }

  virtual void NotifyExpired(LayerActivity* aObject);
};

static LayerActivityTracker* gLayerActivityTracker = nullptr;

LayerActivity::~LayerActivity()
{
  if (mFrame) {
    NS_ASSERTION(gLayerActivityTracker, "Should still have a tracker");
    gLayerActivityTracker->RemoveObject(this);
  }
}

static void DestroyLayerActivity(void* aPropertyValue)
{
  delete static_cast<LayerActivity*>(aPropertyValue);
}

NS_DECLARE_FRAME_PROPERTY(LayerActivityProperty, DestroyLayerActivity)

void
LayerActivityTracker::NotifyExpired(LayerActivity* aObject)
{
  RemoveObject(aObject);

  nsIFrame* f = aObject->mFrame;
  aObject->mFrame = nullptr;

  // if there are hints other than transform/opacity, invalidate, since we don't know what else to do.
  if (aObject->mChangeHint & ~(nsChangeHint_UpdateOpacityLayer|nsChangeHint_UpdateTransformLayer)) {
    f->InvalidateFrameSubtree();
  } else {
    if (aObject->mChangeHint & nsChangeHint_UpdateOpacityLayer) {
      f->InvalidateFrameSubtree(nsDisplayItem::TYPE_OPACITY);
    } 
    if (aObject->mChangeHint & nsChangeHint_UpdateTransformLayer) {
      f->InvalidateFrameSubtree(nsDisplayItem::TYPE_TRANSFORM);
    }
  } 
  f->Properties().Delete(LayerActivityProperty());
}

void
nsIFrame::MarkLayersActive(nsChangeHint aChangeHint)
{
  FrameProperties properties = Properties();
  LayerActivity* layerActivity =
    static_cast<LayerActivity*>(properties.Get(LayerActivityProperty()));
  if (layerActivity) {
    gLayerActivityTracker->MarkUsed(layerActivity);
  } else {
    if (!gLayerActivityTracker) {
      gLayerActivityTracker = new LayerActivityTracker();
    }
    layerActivity = new LayerActivity(this);
    gLayerActivityTracker->AddObject(layerActivity);
    properties.Set(LayerActivityProperty(), layerActivity);
  }
  NS_UpdateHint(layerActivity->mChangeHint, aChangeHint);
}

bool
nsIFrame::AreLayersMarkedActive()
{
  return Properties().Get(LayerActivityProperty()) != nullptr;
}

bool
nsIFrame::AreLayersMarkedActive(nsChangeHint aChangeHint)
{
  LayerActivity* layerActivity =
    static_cast<LayerActivity*>(Properties().Get(LayerActivityProperty()));
  return layerActivity && (layerActivity->mChangeHint & aChangeHint);
}

/* static */ void
nsFrame::ShutdownLayerActivityTimer()
{
  delete gLayerActivityTracker;
  gLayerActivityTracker = nullptr;
}

gfx3DMatrix
nsIFrame::GetTransformMatrix(const nsIFrame* aStopAtAncestor,
                             nsIFrame** aOutAncestor)
{
  NS_PRECONDITION(aOutAncestor, "Need a place to put the ancestor!");

  /* If we're transformed, we want to hand back the combination
   * transform/translate matrix that will apply our current transform, then
   * shift us to our parent.
   */
  if (IsTransformed()) {
    /* Compute the delta to the parent, which we need because we are converting
     * coordinates to our parent.
     */
    NS_ASSERTION(nsLayoutUtils::GetCrossDocParentFrame(this),
                 "Cannot transform the viewport frame!");
    int32_t scaleFactor = PresContext()->AppUnitsPerDevPixel();

    gfx3DMatrix result =
      nsDisplayTransform::GetResultingTransformMatrix(this, nsPoint(0, 0), scaleFactor, nullptr, aOutAncestor);
    // XXXjwatt: seems like this will double count offsets in the face of preserve-3d:
    nsPoint delta = GetOffsetToCrossDoc(*aOutAncestor);
    /* Combine the raw transform with a translation to our parent. */
    result *= gfx3DMatrix::Translation
      (NSAppUnitsToFloatPixels(delta.x, scaleFactor),
       NSAppUnitsToFloatPixels(delta.y, scaleFactor),
       0.0f);
    return result;
  }

  if (nsLayoutUtils::IsPopup(this) &&
      GetType() == nsGkAtoms::listControlFrame) {
    nsPresContext* presContext = PresContext();
    nsIFrame* docRootFrame = presContext->PresShell()->GetRootFrame();

    // Compute a matrix that transforms from the popup widget to the toplevel
    // widget. We use the widgets because they're the simplest and most
    // accurate approach --- this should work no matter how the widget position
    // was chosen.
    nsIWidget* widget = GetView()->GetWidget();
    nsPresContext* rootPresContext = PresContext()->GetRootPresContext();
    // Maybe the widget hasn't been created yet? Popups without widgets are
    // treated as regular frames. That should work since they'll be rendered
    // as part of the page if they're rendered at all.
    if (widget && rootPresContext) {
      nsIWidget* toplevel = rootPresContext->GetNearestWidget();
      if (toplevel) {
        nsIntRect screenBounds;
        widget->GetClientBounds(screenBounds);
        nsIntRect toplevelScreenBounds;
        toplevel->GetClientBounds(toplevelScreenBounds);
        nsIntPoint translation = screenBounds.TopLeft() - toplevelScreenBounds.TopLeft();

        gfx3DMatrix transformToTop;
        transformToTop._41 = translation.x;
        transformToTop._42 = translation.y;

        *aOutAncestor = docRootFrame;
        gfx3DMatrix docRootTransformToTop =
          nsLayoutUtils::GetTransformToAncestor(docRootFrame, nullptr);
        if (docRootTransformToTop.IsSingular()) {
          NS_WARNING("Containing document is invisible, we can't compute a valid transform");
        } else {
          gfx3DMatrix topToDocRootTransform = docRootTransformToTop.Inverse();
          return transformToTop*topToDocRootTransform;
        }
      }
    }
  }

  *aOutAncestor = nsLayoutUtils::GetCrossDocParentFrame(this);

  /* Otherwise, we're not transformed.  In that case, we'll walk up the frame
   * tree until we either hit the root frame or something that may be
   * transformed.  We'll then change coordinates into that frame, since we're
   * guaranteed that nothing in-between can be transformed.  First, however,
   * we have to check to see if we have a parent.  If not, we'll set the
   * outparam to null (indicating that there's nothing left) and will hand back
   * the identity matrix.
   */
  if (!*aOutAncestor)
    return gfx3DMatrix();
  
  /* Keep iterating while the frame can't possibly be transformed. */
  while (!(*aOutAncestor)->IsTransformed() &&
         !nsLayoutUtils::IsPopup(*aOutAncestor) &&
         *aOutAncestor != aStopAtAncestor) {
    /* If no parent, stop iterating.  Otherwise, update the ancestor. */
    nsIFrame* parent = nsLayoutUtils::GetCrossDocParentFrame(*aOutAncestor);
    if (!parent)
      break;

    *aOutAncestor = parent;
  }

  NS_ASSERTION(*aOutAncestor, "Somehow ended up with a null ancestor...?");

  /* Translate from this frame to our ancestor, if it exists.  That's the
   * entire transform, so we're done.
   */
  nsPoint delta = GetOffsetToCrossDoc(*aOutAncestor);
  int32_t scaleFactor = PresContext()->AppUnitsPerDevPixel();
  return gfx3DMatrix().Translation
    (NSAppUnitsToFloatPixels(delta.x, scaleFactor),
     NSAppUnitsToFloatPixels(delta.y, scaleFactor),
     0.0f);
}

static void InvalidateFrameInternal(nsIFrame *aFrame, bool aHasDisplayItem = true)
{
  if (aHasDisplayItem) {
    aFrame->AddStateBits(NS_FRAME_NEEDS_PAINT);
  }
  nsSVGEffects::InvalidateDirectRenderingObservers(aFrame);
  bool needsSchedulePaint = false;
  if (nsLayoutUtils::IsPopup(aFrame)) {
    needsSchedulePaint = true;
  } else {
    nsIFrame *parent = nsLayoutUtils::GetCrossDocParentFrame(aFrame);
    while (parent && !parent->HasAnyStateBits(NS_FRAME_DESCENDANT_NEEDS_PAINT)) {
      if (aHasDisplayItem) {
        parent->AddStateBits(NS_FRAME_DESCENDANT_NEEDS_PAINT);
      }
      nsSVGEffects::InvalidateDirectRenderingObservers(parent);

      // If we're inside a popup, then we need to make sure that we
      // call schedule paint so that the NS_FRAME_UPDATE_LAYER_TREE
      // flag gets added to the popup display root frame.
      if (nsLayoutUtils::IsPopup(parent)) {
        needsSchedulePaint = true;
        break;
      }
      parent = nsLayoutUtils::GetCrossDocParentFrame(parent);
    }
    if (!parent) {
      needsSchedulePaint = true;
    }
  }
  if (!aHasDisplayItem) {
    return;
  }
  if (needsSchedulePaint) {
    aFrame->SchedulePaint();
  }
  if (aFrame->HasAnyStateBits(NS_FRAME_HAS_INVALID_RECT)) {
    aFrame->Properties().Delete(nsIFrame::InvalidationRect());
    aFrame->RemoveStateBits(NS_FRAME_HAS_INVALID_RECT);
  }
}

void
nsIFrame::InvalidateFrameSubtree(uint32_t aDisplayItemKey)
{
  bool hasDisplayItem = 
    !aDisplayItemKey || FrameLayerBuilder::HasRetainedDataFor(this, aDisplayItemKey);
  InvalidateFrame(aDisplayItemKey);

  if (HasAnyStateBits(NS_FRAME_ALL_DESCENDANTS_NEED_PAINT) || !hasDisplayItem) {
    return;
  }

  AddStateBits(NS_FRAME_ALL_DESCENDANTS_NEED_PAINT);
  
  nsAutoTArray<nsIFrame::ChildList,4> childListArray;
  GetCrossDocChildLists(&childListArray);

  nsIFrame::ChildListArrayIterator lists(childListArray);
  for (; !lists.IsDone(); lists.Next()) {
    nsFrameList::Enumerator childFrames(lists.CurrentList());
    for (; !childFrames.AtEnd(); childFrames.Next()) {
      childFrames.get()->InvalidateFrameSubtree();
    }
  }
}

void
nsIFrame::ClearInvalidationStateBits()
{
  if (HasAnyStateBits(NS_FRAME_DESCENDANT_NEEDS_PAINT)) {
    nsAutoTArray<nsIFrame::ChildList,4> childListArray;
    GetCrossDocChildLists(&childListArray);

    nsIFrame::ChildListArrayIterator lists(childListArray);
    for (; !lists.IsDone(); lists.Next()) {
      nsFrameList::Enumerator childFrames(lists.CurrentList());
      for (; !childFrames.AtEnd(); childFrames.Next()) {
        childFrames.get()->ClearInvalidationStateBits();
      }
    }
  }

  RemoveStateBits(NS_FRAME_NEEDS_PAINT | 
                  NS_FRAME_DESCENDANT_NEEDS_PAINT | 
                  NS_FRAME_ALL_DESCENDANTS_NEED_PAINT);
}

void
nsIFrame::InvalidateFrame(uint32_t aDisplayItemKey)
{
  bool hasDisplayItem = 
    !aDisplayItemKey || FrameLayerBuilder::HasRetainedDataFor(this, aDisplayItemKey);
  InvalidateFrameInternal(this, hasDisplayItem);
}

void
nsIFrame::InvalidateFrameWithRect(const nsRect& aRect, uint32_t aDisplayItemKey)
{
  bool hasDisplayItem = 
    !aDisplayItemKey || FrameLayerBuilder::HasRetainedDataFor(this, aDisplayItemKey);
  bool alreadyInvalid = false;
  if (!HasAnyStateBits(NS_FRAME_NEEDS_PAINT)) {
    InvalidateFrameInternal(this, hasDisplayItem);
  } else {
    alreadyInvalid = true;
  } 

  if (!hasDisplayItem) {
    return;
  }

  nsRect *rect = static_cast<nsRect*>(Properties().Get(InvalidationRect()));
  if (!rect) {
    if (alreadyInvalid) {
      return;
    }
    rect = new nsRect();
    Properties().Set(InvalidationRect(), rect);
    AddStateBits(NS_FRAME_HAS_INVALID_RECT);
  }

  *rect = rect->Union(aRect);
}

/*static*/ uint8_t nsIFrame::sLayerIsPrerenderedDataKey;

bool
nsIFrame::TryUpdateTransformOnly()
{
  Layer* layer = FrameLayerBuilder::GetDedicatedLayer(
    this, nsDisplayItem::TYPE_TRANSFORM);
  if (!layer || !layer->HasUserData(LayerIsPrerenderedDataKey())) {
    // If this layer isn't prerendered or we clip composites to our OS
    // window, then we can't correctly optimize to an empty
    // transaction in general.
    return false;
  }

  gfx3DMatrix transform3d;
  if (!nsLayoutUtils::GetLayerTransformForFrame(this, &transform3d)) {
    // We're not able to compute a layer transform that we know would
    // be used at the next layers transaction, so we can't only update
    // the transform and will need to schedule an invalidating paint.
    return false;
  }
  gfxMatrix transform, previousTransform;
  // FIXME/bug 796690 and 796705: in general, changes to 3D
  // transforms, or transform changes to properties other than
  // translation, may lead us to choose a different rendering
  // resolution for our layer.  So if the transform is 3D or has a
  // non-translation change, bail and schedule an invalidating paint.
  // (We can often do better than this, for example for scale-down
  // changes.)
 static const gfx::Float kError = 0.0001;
  if (!transform3d.Is2D(&transform) ||
      !layer->GetBaseTransform().Is2D(&previousTransform) ||
      !gfx::FuzzyEqual(transform.xx, previousTransform.xx, kError) ||
      !gfx::FuzzyEqual(transform.yy, previousTransform.yy, kError) ||
      !gfx::FuzzyEqual(transform.xy, previousTransform.xy, kError) ||
      !gfx::FuzzyEqual(transform.yx, previousTransform.yx, kError)) {
    return false;
  }
  layer->SetBaseTransformForNextTransaction(transform3d);
  return true;
}

bool 
nsIFrame::IsInvalid(nsRect& aRect)
{
  if (!HasAnyStateBits(NS_FRAME_NEEDS_PAINT)) {
    return false;
  }
  
  if (HasAnyStateBits(NS_FRAME_HAS_INVALID_RECT)) {
    nsRect *rect = static_cast<nsRect*>(Properties().Get(InvalidationRect()));
    NS_ASSERTION(rect, "Must have an invalid rect if NS_FRAME_HAS_INVALID_RECT is set!");
    aRect = *rect;
  } else {
    aRect.SetEmpty();
  }
  return true;
}

void
nsIFrame::SchedulePaint(uint32_t aFlags)
{
  nsIFrame *displayRoot = nsLayoutUtils::GetDisplayRootFrame(this);
  nsPresContext *pres = displayRoot->PresContext()->GetRootPresContext();

  // No need to schedule a paint for an external document since they aren't
  // painted directly.
  if (!pres || (pres->Document() && pres->Document()->GetDisplayDocument())) {
    return;
  }
  
  pres->PresShell()->ScheduleViewManagerFlush();
  if (!(aFlags & PAINT_COMPOSITE_ONLY)) {
    displayRoot->AddStateBits(NS_FRAME_UPDATE_LAYER_TREE);
  }
  nsIPresShell* shell = PresContext()->PresShell();
  if (shell) {
    shell->AddInvalidateHiddenPresShellObserver(pres->RefreshDriver());
  }
}

Layer*
nsIFrame::InvalidateLayer(uint32_t aDisplayItemKey, const nsIntRect* aDamageRect)
{
  NS_ASSERTION(aDisplayItemKey > 0, "Need a key");

  Layer* layer = FrameLayerBuilder::GetDedicatedLayer(this, aDisplayItemKey);
  if (aDamageRect && aDamageRect->IsEmpty()) {
    return layer;
  }

  if (!layer) {
    // Plugins can transition from not rendering anything to rendering,
    // and still only call this. So always invalidate, with specifying
    // the display item type just in case.
    if (aDisplayItemKey == nsDisplayItem::TYPE_PLUGIN) {
      InvalidateFrame();
    } else {
      InvalidateFrame(aDisplayItemKey);
    }
    return nullptr;
  }

  if (aDamageRect) {
    layer->AddInvalidRect(*aDamageRect);
  } else {
    layer->SetInvalidRectToVisibleRegion();
  }

  SchedulePaint(PAINT_COMPOSITE_ONLY);
  return layer;
}

NS_DECLARE_FRAME_PROPERTY(DeferInvalidatesProperty, nsIFrame::DestroyRegion)

void
nsIFrame::BeginDeferringInvalidatesForDisplayRoot(const nsRegion& aExcludeRegion)
{
  NS_ASSERTION(nsLayoutUtils::GetDisplayRootFrame(this) == this,
               "Can only call this on display roots");
  Properties().Set(DeferInvalidatesProperty(), new nsRegion(aExcludeRegion));
}

void
nsIFrame::EndDeferringInvalidatesForDisplayRoot()
{
  NS_ASSERTION(nsLayoutUtils::GetDisplayRootFrame(this) == this,
               "Can only call this on display roots");
  Properties().Delete(DeferInvalidatesProperty());
}

/**
 * @param aAnyOutlineOrEffects set to true if this frame has any
 * outline, SVG effects or box shadows that mean we need to invalidate
 * the whole overflow area if the frame's size changes.
 */
static nsRect
ComputeOutlineAndEffectsRect(nsIFrame* aFrame,
                             const nsRect& aOverflowRect,
                             const nsSize& aNewSize,
                             bool aStoreRectProperties) {
  nsRect r = aOverflowRect;

  if (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT) {
    // For SVG frames, we only need to account for filters.
    // TODO: We could also take account of clipPath and mask to reduce the
    // visual overflow, but that's not essential.
    if (aFrame->StyleSVGReset()->mFilter) {
      if (aStoreRectProperties) {
        aFrame->Properties().
          Set(nsIFrame::PreEffectsBBoxProperty(), new nsRect(r));
      }
      r = nsSVGUtils::GetPostFilterVisualOverflowRect(aFrame, aOverflowRect);
    }
    return r;
  }

  // box-shadow
  r.UnionRect(r, nsLayoutUtils::GetBoxShadowRectForFrame(aFrame, aNewSize));

  const nsStyleOutline* outline = aFrame->StyleOutline();
  uint8_t outlineStyle = outline->GetOutlineStyle();
  if (outlineStyle != NS_STYLE_BORDER_STYLE_NONE) {
    nscoord width;
#ifdef DEBUG
    bool result = 
#endif
      outline->GetOutlineWidth(width);
    NS_ASSERTION(result, "GetOutlineWidth had no cached outline width");
    if (width > 0) {
      if (aStoreRectProperties) {
        aFrame->Properties().
          Set(nsIFrame::OutlineInnerRectProperty(), new nsRect(r));
      }

      nscoord offset = outline->mOutlineOffset;
      nscoord inflateBy = std::max(width + offset, 0);
      // FIXME (bug 599652): We probably want outline to be drawn around
      // something smaller than the visual overflow rect (perhaps the
      // scrollable overflow rect is correct).  When we change that, we
      // need to keep this code (and the storing of properties just
      // above) in sync with GetOutlineInnerRect in nsCSSRendering.cpp.
      r.Inflate(inflateBy, inflateBy);
    }
  }

  // border-image-outset.
  // We need to include border-image-outset because it can cause the
  // border image to be drawn beyond the border box.

  // (1) It's important we not check whether there's a border-image
  //     since the style hint for a change in border image doesn't cause
  //     reflow, and that's probably more important than optimizing the
  //     overflow areas for the silly case of border-image-outset without
  //     border-image
  // (2) It's important that we not check whether the border-image
  //     is actually loaded, since that would require us to reflow when
  //     the image loads.
  const nsStyleBorder* styleBorder = aFrame->StyleBorder();
  nsMargin outsetMargin = styleBorder->GetImageOutset();

  if (outsetMargin != nsMargin(0, 0, 0, 0)) {
    nsRect outsetRect(nsPoint(0, 0), aNewSize);
    outsetRect.Inflate(outsetMargin);
    r.UnionRect(r, outsetRect);
  }

  // Note that we don't remove the outlineInnerRect if a frame loses outline
  // style. That would require an extra property lookup for every frame,
  // or a new frame state bit to track whether a property had been stored,
  // or something like that. It's not worth doing that here. At most it's
  // only one heap-allocated rect per frame and it will be cleaned up when
  // the frame dies.

  if (nsSVGIntegrationUtils::UsingEffectsForFrame(aFrame)) {
    if (aStoreRectProperties) {
      aFrame->Properties().
        Set(nsIFrame::PreEffectsBBoxProperty(), new nsRect(r));
    }
    r = nsSVGIntegrationUtils::ComputePostEffectsVisualOverflowRect(aFrame, r);
  }

  return r;
}

nsPoint
nsIFrame::GetRelativeOffset(const nsStyleDisplay* aDisplay) const
{
  if (!aDisplay ||
      aDisplay->IsRelativelyPositioned(this)) {
    nsPoint *offsets = static_cast<nsPoint*>
      (Properties().Get(ComputedOffsetProperty()));
    if (offsets) {
      return *offsets;
    }
  }
  return nsPoint(0,0);
}

nsRect
nsIFrame::GetOverflowRect(nsOverflowType aType) const
{
  NS_ABORT_IF_FALSE(aType == eVisualOverflow || aType == eScrollableOverflow,
                    "unexpected type");

  // Note that in some cases the overflow area might not have been
  // updated (yet) to reflect any outline set on the frame or the area
  // of child frames. That's OK because any reflow that updates these
  // areas will invalidate the appropriate area, so any (mis)uses of
  // this method will be fixed up.

  if (mOverflow.mType == NS_FRAME_OVERFLOW_LARGE) {
    // there is an overflow rect, and it's not stored as deltas but as
    // a separately-allocated rect
    return static_cast<nsOverflowAreas*>(const_cast<nsIFrame*>(this)->
             GetOverflowAreasProperty())->Overflow(aType);
  }

  if (aType == eVisualOverflow &&
      mOverflow.mType != NS_FRAME_OVERFLOW_NONE) {
    return GetVisualOverflowFromDeltas();
  }

  return nsRect(nsPoint(0, 0), GetSize());
}

nsOverflowAreas
nsIFrame::GetOverflowAreas() const
{
  if (mOverflow.mType == NS_FRAME_OVERFLOW_LARGE) {
    // there is an overflow rect, and it's not stored as deltas but as
    // a separately-allocated rect
    return *const_cast<nsIFrame*>(this)->GetOverflowAreasProperty();
  }

  return nsOverflowAreas(GetVisualOverflowFromDeltas(),
                         nsRect(nsPoint(0, 0), GetSize()));
}

nsRect
nsIFrame::GetScrollableOverflowRectRelativeToParent() const
{
  return GetScrollableOverflowRect() + mRect.TopLeft();
}

nsRect
nsIFrame::GetVisualOverflowRectRelativeToSelf() const
{
  if (IsTransformed()) {
    nsOverflowAreas* preTransformOverflows = static_cast<nsOverflowAreas*>
      (Properties().Get(PreTransformOverflowAreasProperty()));
    if (preTransformOverflows)
      return preTransformOverflows->VisualOverflow();
  }
  return GetVisualOverflowRect();
}

nsRect
nsIFrame::GetPreEffectsVisualOverflowRect() const
{
  nsRect* r = static_cast<nsRect*>
    (Properties().Get(nsIFrame::PreEffectsBBoxProperty()));
  return r ? *r : GetVisualOverflowRectRelativeToSelf();
}

/* virtual */ bool
nsFrame::UpdateOverflow()
{
  MOZ_ASSERT(!(mState & NS_FRAME_SVG_LAYOUT) ||
             !(mState & NS_STATE_SVG_NONDISPLAY_CHILD),
             "Non-display SVG do not maintain visual overflow rects");

  nsRect rect(nsPoint(0, 0), GetSize());
  nsOverflowAreas overflowAreas(rect, rect);

  bool isBox = IsBoxFrame() || IsBoxWrapped();
  if (!isBox || (!IsCollapsed() && !DoesClipChildren())) {
    nsLayoutUtils::UnionChildOverflow(this, overflowAreas);
  }

  if (FinishAndStoreOverflow(overflowAreas, GetSize())) {
    nsView* view = GetView();
    if (view) {
      uint32_t flags = 0;
      GetLayoutFlags(flags);

      if ((flags & NS_FRAME_NO_SIZE_VIEW) == 0) {
        // Make sure the frame's view is properly sized.
        nsViewManager* vm = view->GetViewManager();
        vm->ResizeView(view, overflowAreas.VisualOverflow(), true);
      }
    }

    return true;
  }

  return false;
}

// Define the MAX_FRAME_DEPTH to be the ContentSink's MAX_REFLOW_DEPTH plus
// 4 for the frames above the document's frames: 
//  the Viewport, GFXScroll, ScrollPort, and Canvas
#define MAX_FRAME_DEPTH (MAX_REFLOW_DEPTH+4)

bool
nsFrame::IsFrameTreeTooDeep(const nsHTMLReflowState& aReflowState,
                            nsHTMLReflowMetrics& aMetrics,
                            nsReflowStatus& aStatus)
{
  if (aReflowState.mReflowDepth >  MAX_FRAME_DEPTH) {
    NS_WARNING("frame tree too deep; setting zero size and returning");
    mState |= NS_FRAME_TOO_DEEP_IN_FRAME_TREE;
    ClearOverflowRects();
    aMetrics.width = 0;
    aMetrics.height = 0;
    aMetrics.ascent = 0;
    aMetrics.mCarriedOutBottomMargin.Zero();
    aMetrics.mOverflowAreas.Clear();

    if (GetNextInFlow()) {
      // Reflow depth might vary between reflows, so we might have
      // successfully reflowed and split this frame before.  If so, we
      // shouldn't delete its continuations.
      aStatus = NS_FRAME_NOT_COMPLETE;
    } else {
      aStatus = NS_FRAME_COMPLETE;
    }

    return true;
  }
  mState &= ~NS_FRAME_TOO_DEEP_IN_FRAME_TREE;
  return false;
}

bool
nsIFrame::IsBlockWrapper() const
{
  nsIAtom *pseudoType = StyleContext()->GetPseudo();
  return (pseudoType == nsCSSAnonBoxes::mozAnonymousBlock ||
          pseudoType == nsCSSAnonBoxes::mozAnonymousPositionedBlock ||
          pseudoType == nsCSSAnonBoxes::cellContent);
}

static nsIFrame*
GetNearestBlockContainer(nsIFrame* frame)
{
  // The block wrappers we use to wrap blocks inside inlines aren't
  // described in the CSS spec.  We need to make them not be containing
  // blocks.
  // Since the parent of such a block is either a normal block or
  // another such pseudo, this shouldn't cause anything bad to happen.
  // Also the anonymous blocks inside table cells are not containing blocks.
  while (frame->IsFrameOfType(nsIFrame::eLineParticipant) ||
         frame->IsBlockWrapper() ||
         // Table rows are not containing blocks either
         frame->GetType() == nsGkAtoms::tableRowFrame) {
    frame = frame->GetParent();
    NS_ASSERTION(frame, "How come we got to the root frame without seeing a containing block?");
  }
  return frame;
}

nsIFrame*
nsIFrame::GetContainingBlock() const
{
  // MathML frames might have absolute positioning style, but they would
  // still be in-flow.  So we have to check to make sure that the frame
  // is really out-of-flow too.
  if (IsAbsolutelyPositioned() &&
      (GetStateBits() & NS_FRAME_OUT_OF_FLOW)) {
    return GetParent(); // the parent is always the containing block
  }
  return GetNearestBlockContainer(GetParent());
}

#ifdef DEBUG

int32_t nsFrame::ContentIndexInContainer(const nsIFrame* aFrame)
{
  int32_t result = -1;

  nsIContent* content = aFrame->GetContent();
  if (content) {
    nsIContent* parentContent = content->GetParent();
    if (parentContent) {
      result = parentContent->IndexOf(content);
    }
  }

  return result;
}

/**
 * List a frame tree to stdout. Meant to be called from gdb.
 */
void
DebugListFrameTree(nsIFrame* aFrame)
{
  ((nsFrame*)aFrame)->List(stdout, 0);
}


// Debugging
NS_IMETHODIMP
nsFrame::List(FILE* out, int32_t aIndent, uint32_t aFlags) const
{
  IndentBy(out, aIndent);
  ListTag(out);
#ifdef DEBUG_waterson
  fprintf(out, " [parent=%p]", static_cast<void*>(mParent));
#endif
  if (HasView()) {
    fprintf(out, " [view=%p]", static_cast<void*>(GetView()));
  }
  fprintf(out, " {%d,%d,%d,%d}", mRect.x, mRect.y, mRect.width, mRect.height);
  if (0 != mState) {
    fprintf(out, " [state=%016llx]", (unsigned long long)mState);
  }
  nsIFrame* prevInFlow = GetPrevInFlow();
  nsIFrame* nextInFlow = GetNextInFlow();
  if (nullptr != prevInFlow) {
    fprintf(out, " prev-in-flow=%p", static_cast<void*>(prevInFlow));
  }
  if (nullptr != nextInFlow) {
    fprintf(out, " next-in-flow=%p", static_cast<void*>(nextInFlow));
  }
  fprintf(out, " [content=%p]", static_cast<void*>(mContent));
  nsFrame* f = const_cast<nsFrame*>(this);
  if (f->HasOverflowAreas()) {
    nsRect overflowArea = f->GetVisualOverflowRect();
    fprintf(out, " [vis-overflow=%d,%d,%d,%d]", overflowArea.x, overflowArea.y,
            overflowArea.width, overflowArea.height);
    overflowArea = f->GetScrollableOverflowRect();
    fprintf(out, " [scr-overflow=%d,%d,%d,%d]", overflowArea.x, overflowArea.y,
            overflowArea.width, overflowArea.height);
  }
  fprintf(out, " [sc=%p]", static_cast<void*>(mStyleContext));
  fputs("\n", out);
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::GetFrameName(nsAString& aResult) const
{
  return MakeFrameName(NS_LITERAL_STRING("Frame"), aResult);
}

NS_IMETHODIMP_(nsFrameState)
nsFrame::GetDebugStateBits() const
{
  // We'll ignore these flags for the purposes of comparing frame state:
  //
  //   NS_FRAME_EXTERNAL_REFERENCE
  //     because this is set by the event state manager or the
  //     caret code when a frame is focused. Depending on whether
  //     or not the regression tests are run as the focused window
  //     will make this value vary randomly.
#define IRRELEVANT_FRAME_STATE_FLAGS NS_FRAME_EXTERNAL_REFERENCE

#define FRAME_STATE_MASK (~(IRRELEVANT_FRAME_STATE_FLAGS))

  return GetStateBits() & FRAME_STATE_MASK;
}

nsresult
nsFrame::MakeFrameName(const nsAString& aType, nsAString& aResult) const
{
  aResult = aType;
  if (mContent && !mContent->IsNodeOfType(nsINode::eTEXT)) {
    nsAutoString buf;
    mContent->Tag()->ToString(buf);
    if (GetType() == nsGkAtoms::subDocumentFrame) {
      nsAutoString src;
      mContent->GetAttr(kNameSpaceID_None, nsGkAtoms::src, src);
      buf.Append(NS_LITERAL_STRING(" src=") + src);
    }
    aResult.Append(NS_LITERAL_STRING("(") + buf + NS_LITERAL_STRING(")"));
  }
  char buf[40];
  PR_snprintf(buf, sizeof(buf), "(%d)", ContentIndexInContainer(this));
  AppendASCIItoUTF16(buf, aResult);
  return NS_OK;
}

void
nsFrame::XMLQuote(nsString& aString)
{
  int32_t i, len = aString.Length();
  for (i = 0; i < len; i++) {
    PRUnichar ch = aString.CharAt(i);
    if (ch == '<') {
      nsAutoString tmp(NS_LITERAL_STRING("&lt;"));
      aString.Cut(i, 1);
      aString.Insert(tmp, i);
      len += 3;
      i += 3;
    }
    else if (ch == '>') {
      nsAutoString tmp(NS_LITERAL_STRING("&gt;"));
      aString.Cut(i, 1);
      aString.Insert(tmp, i);
      len += 3;
      i += 3;
    }
    else if (ch == '\"') {
      nsAutoString tmp(NS_LITERAL_STRING("&quot;"));
      aString.Cut(i, 1);
      aString.Insert(tmp, i);
      len += 5;
      i += 5;
    }
  }
}
#endif

bool
nsIFrame::IsVisibleForPainting(nsDisplayListBuilder* aBuilder) {
  if (!StyleVisibility()->IsVisible())
    return false;
  nsISelection* sel = aBuilder->GetBoundingSelection();
  return !sel || IsVisibleInSelection(sel);
}

bool
nsIFrame::IsVisibleForPainting() {
  if (!StyleVisibility()->IsVisible())
    return false;

  nsPresContext* pc = PresContext();
  if (!pc->IsRenderingOnlySelection())
    return true;

  nsCOMPtr<nsISelectionController> selcon(do_QueryInterface(pc->PresShell()));
  if (selcon) {
    nsCOMPtr<nsISelection> sel;
    selcon->GetSelection(nsISelectionController::SELECTION_NORMAL,
                         getter_AddRefs(sel));
    if (sel)
      return IsVisibleInSelection(sel);
  }
  return true;
}

bool
nsIFrame::IsVisibleInSelection(nsDisplayListBuilder* aBuilder) {
  nsISelection* sel = aBuilder->GetBoundingSelection();
  return !sel || IsVisibleInSelection(sel);
}

bool
nsIFrame::IsVisibleOrCollapsedForPainting(nsDisplayListBuilder* aBuilder) {
  if (!StyleVisibility()->IsVisibleOrCollapsed())
    return false;
  nsISelection* sel = aBuilder->GetBoundingSelection();
  return !sel || IsVisibleInSelection(sel);
}

bool
nsIFrame::IsVisibleInSelection(nsISelection* aSelection)
{
  if (!GetContent() || !GetContent()->IsSelectionDescendant()) {
    return false;
  }
  
  nsCOMPtr<nsIDOMNode> node(do_QueryInterface(mContent));
  bool vis;
  nsresult rv = aSelection->ContainsNode(node, true, &vis);
  return NS_FAILED(rv) || vis;
}

/* virtual */ bool
nsFrame::IsEmpty()
{
  return false;
}

bool
nsIFrame::CachedIsEmpty()
{
  NS_PRECONDITION(!(GetStateBits() & NS_FRAME_IS_DIRTY),
                  "Must only be called on reflowed lines");
  return IsEmpty();
}

/* virtual */ bool
nsFrame::IsSelfEmpty()
{
  return false;
}

NS_IMETHODIMP
nsFrame::GetSelectionController(nsPresContext *aPresContext, nsISelectionController **aSelCon)
{
  if (!aPresContext || !aSelCon)
    return NS_ERROR_INVALID_ARG;

  nsIFrame *frame = this;
  while (frame && (frame->GetStateBits() & NS_FRAME_INDEPENDENT_SELECTION)) {
    nsITextControlFrame *tcf = do_QueryFrame(frame);
    if (tcf) {
      return tcf->GetOwnedSelectionController(aSelCon);
    }
    frame = frame->GetParent();
  }

  return CallQueryInterface(aPresContext->GetPresShell(), aSelCon);
}

already_AddRefed<nsFrameSelection>
nsIFrame::GetFrameSelection()
{
  nsFrameSelection* fs =
    const_cast<nsFrameSelection*>(GetConstFrameSelection());
  NS_IF_ADDREF(fs);
  return fs;
}

const nsFrameSelection*
nsIFrame::GetConstFrameSelection() const
{
  nsIFrame* frame = const_cast<nsIFrame*>(this);
  while (frame && (frame->GetStateBits() & NS_FRAME_INDEPENDENT_SELECTION)) {
    nsITextControlFrame* tcf = do_QueryFrame(frame);
    if (tcf) {
      return tcf->GetOwnedFrameSelection();
    }
    frame = frame->GetParent();
  }

  return PresContext()->PresShell()->ConstFrameSelection();
}

#ifdef DEBUG
NS_IMETHODIMP
nsFrame::DumpRegressionData(nsPresContext* aPresContext, FILE* out, int32_t aIndent)
{
  IndentBy(out, aIndent);
  fprintf(out, "<frame va=\"%p\" type=\"", (void*)this);
  nsAutoString name;
  GetFrameName(name);
  XMLQuote(name);
  fputs(NS_LossyConvertUTF16toASCII(name).get(), out);
  fprintf(out, "\" state=\"%016llx\" parent=\"%p\">\n",
          (unsigned long long)GetDebugStateBits(), (void*)mParent);

  aIndent++;
  DumpBaseRegressionData(aPresContext, out, aIndent);
  aIndent--;

  IndentBy(out, aIndent);
  fprintf(out, "</frame>\n");

  return NS_OK;
}

void
nsFrame::DumpBaseRegressionData(nsPresContext* aPresContext, FILE* out, int32_t aIndent)
{
  if (GetNextSibling()) {
    IndentBy(out, aIndent);
    fprintf(out, "<next-sibling va=\"%p\"/>\n", (void*)GetNextSibling());
  }

  if (HasView()) {
    IndentBy(out, aIndent);
    fprintf(out, "<view va=\"%p\">\n", (void*)GetView());
    aIndent++;
    // XXX add in code to dump out view state too...
    aIndent--;
    IndentBy(out, aIndent);
    fprintf(out, "</view>\n");
  }

  IndentBy(out, aIndent);
  fprintf(out, "<bbox x=\"%d\" y=\"%d\" w=\"%d\" h=\"%d\"/>\n",
          mRect.x, mRect.y, mRect.width, mRect.height);

  // Now dump all of the children on all of the child lists
  ChildListIterator lists(this);
  for (; !lists.IsDone(); lists.Next()) {
    IndentBy(out, aIndent);
    if (lists.CurrentID() != kPrincipalList) {
      fprintf(out, "<child-list name=\"%s\">\n", mozilla::layout::ChildListName(lists.CurrentID()));
    }
    else {
      fprintf(out, "<child-list>\n");
    }
    aIndent++;
    nsFrameList::Enumerator childFrames(lists.CurrentList());
    for (; !childFrames.AtEnd(); childFrames.Next()) {
      nsIFrame* kid = childFrames.get();
      kid->DumpRegressionData(aPresContext, out, aIndent);
    }
    aIndent--;
    IndentBy(out, aIndent);
    fprintf(out, "</child-list>\n");
  }
}
#endif

bool
nsIFrame::IsFrameSelected() const
{
  NS_ASSERTION(!GetContent() || GetContent()->IsSelectionDescendant(),
               "use the public IsSelected() instead");
  return nsRange::IsNodeSelected(GetContent(), 0,
                                 GetContent()->GetChildCount());
}

NS_IMETHODIMP
nsFrame::GetPointFromOffset(int32_t inOffset, nsPoint* outPoint)
{
  NS_PRECONDITION(outPoint != nullptr, "Null parameter");
  nsRect contentRect = GetContentRect() - GetPosition();
  nsPoint pt = contentRect.TopLeft();
  if (mContent)
  {
    nsIContent* newContent = mContent->GetParent();
    if (newContent){
      int32_t newOffset = newContent->IndexOf(mContent);

      bool isRTL = (NS_GET_EMBEDDING_LEVEL(this) & 1) == 1;
      if ((!isRTL && inOffset > newOffset) ||
          (isRTL && inOffset <= newOffset)) {
        pt = contentRect.TopRight();
      }
    }
  }
  *outPoint = pt;
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::GetChildFrameContainingOffset(int32_t inContentOffset, bool inHint, int32_t* outFrameContentOffset, nsIFrame **outChildFrame)
{
  NS_PRECONDITION(outChildFrame && outFrameContentOffset, "Null parameter");
  *outFrameContentOffset = (int32_t)inHint;
  //the best frame to reflect any given offset would be a visible frame if possible
  //i.e. we are looking for a valid frame to place the blinking caret 
  nsRect rect = GetRect();
  if (!rect.width || !rect.height)
  {
    //if we have a 0 width or height then lets look for another frame that possibly has
    //the same content.  If we have no frames in flow then just let us return 'this' frame
    nsIFrame* nextFlow = GetNextInFlow();
    if (nextFlow)
      return nextFlow->GetChildFrameContainingOffset(inContentOffset, inHint, outFrameContentOffset, outChildFrame);
  }
  *outChildFrame = this;
  return NS_OK;
}

//
// What I've pieced together about this routine:
// Starting with a block frame (from which a line frame can be gotten)
// and a line number, drill down and get the first/last selectable
// frame on that line, depending on aPos->mDirection.
// aOutSideLimit != 0 means ignore aLineStart, instead work from
// the end (if > 0) or beginning (if < 0).
//
nsresult
nsFrame::GetNextPrevLineFromeBlockFrame(nsPresContext* aPresContext,
                                        nsPeekOffsetStruct *aPos,
                                        nsIFrame *aBlockFrame, 
                                        int32_t aLineStart, 
                                        int8_t aOutSideLimit
                                        )
{
  //magic numbers aLineStart will be -1 for end of block 0 will be start of block
  if (!aBlockFrame || !aPos)
    return NS_ERROR_NULL_POINTER;

  aPos->mResultFrame = nullptr;
  aPos->mResultContent = nullptr;
  aPos->mAttachForward = (aPos->mDirection == eDirNext);

  nsAutoLineIterator it = aBlockFrame->GetLineIterator();
  if (!it)
    return NS_ERROR_FAILURE;
  int32_t searchingLine = aLineStart;
  int32_t countLines = it->GetNumLines();
  if (aOutSideLimit > 0) //start at end
    searchingLine = countLines;
  else if (aOutSideLimit <0)//start at beginning
    searchingLine = -1;//"next" will be 0  
  else 
    if ((aPos->mDirection == eDirPrevious && searchingLine == 0) || 
       (aPos->mDirection == eDirNext && searchingLine >= (countLines -1) )){
      //we need to jump to new block frame.
           return NS_ERROR_FAILURE;
    }
  int32_t lineFrameCount;
  nsIFrame *resultFrame = nullptr;
  nsIFrame *farStoppingFrame = nullptr; //we keep searching until we find a "this" frame then we go to next line
  nsIFrame *nearStoppingFrame = nullptr; //if we are backing up from edge, stop here
  nsIFrame *firstFrame;
  nsIFrame *lastFrame;
  nsRect  rect;
  bool isBeforeFirstFrame, isAfterLastFrame;
  bool found = false;

  nsresult result = NS_OK;
  while (!found)
  {
    if (aPos->mDirection == eDirPrevious)
      searchingLine --;
    else
      searchingLine ++;
    if ((aPos->mDirection == eDirPrevious && searchingLine < 0) || 
       (aPos->mDirection == eDirNext && searchingLine >= countLines ))
    {
      //we need to jump to new block frame.
      return NS_ERROR_FAILURE;
    }
    uint32_t lineFlags;
    result = it->GetLine(searchingLine, &firstFrame, &lineFrameCount,
                         rect, &lineFlags);
    if (!lineFrameCount) 
      continue;
    if (NS_SUCCEEDED(result)){
      lastFrame = firstFrame;
      for (;lineFrameCount > 1;lineFrameCount --){
        //result = lastFrame->GetNextSibling(&lastFrame, searchingLine);
        result = it->GetNextSiblingOnLine(lastFrame, searchingLine);
        if (NS_FAILED(result) || !lastFrame){
          NS_ERROR("GetLine promised more frames than could be found");
          return NS_ERROR_FAILURE;
        }
      }
      GetLastLeaf(aPresContext, &lastFrame);

      if (aPos->mDirection == eDirNext){
        nearStoppingFrame = firstFrame;
        farStoppingFrame = lastFrame;
      }
      else{
        nearStoppingFrame = lastFrame;
        farStoppingFrame = firstFrame;
      }
      nsPoint offset;
      nsView * view; //used for call of get offset from view
      aBlockFrame->GetOffsetFromView(offset,&view);
      nscoord newDesiredX  = aPos->mDesiredX - offset.x;//get desired x into blockframe coordinates!
      result = it->FindFrameAt(searchingLine, newDesiredX, &resultFrame, &isBeforeFirstFrame, &isAfterLastFrame);
      if(NS_FAILED(result))
        continue;
    }

    if (NS_SUCCEEDED(result) && resultFrame)
    {
      //check to see if this is ANOTHER blockframe inside the other one if so then call into its lines
      nsAutoLineIterator newIt = resultFrame->GetLineIterator();
      if (newIt)
      {
        aPos->mResultFrame = resultFrame;
        return NS_OK;
      }
      //resultFrame is not a block frame
      result = NS_ERROR_FAILURE;

      nsCOMPtr<nsIFrameEnumerator> frameTraversal;
      result = NS_NewFrameTraversal(getter_AddRefs(frameTraversal),
                                    aPresContext, resultFrame,
                                    ePostOrder,
                                    false, // aVisual
                                    aPos->mScrollViewStop,
                                    false     // aFollowOOFs
                                    );
      if (NS_FAILED(result))
        return result;

      nsIFrame *storeOldResultFrame = resultFrame;
      while ( !found ){
        nsPoint point;
        point.x = aPos->mDesiredX;

        nsRect tempRect = resultFrame->GetRect();
        nsPoint offset;
        nsView * view; //used for call of get offset from view
        result = resultFrame->GetOffsetFromView(offset, &view);
        if (NS_FAILED(result))
          return result;
        point.y = tempRect.height + offset.y;

        //special check. if we allow non-text selection then we can allow a hit location to fall before a table.
        //otherwise there is no way to get and click signal to fall before a table (it being a line iterator itself)
        nsIPresShell *shell = aPresContext->GetPresShell();
        if (!shell)
          return NS_ERROR_FAILURE;
        int16_t isEditor = shell->GetSelectionFlags();
        isEditor = isEditor == nsISelectionDisplay::DISPLAY_ALL;
        if ( isEditor )
        {
          if (resultFrame->GetType() == nsGkAtoms::tableOuterFrame)
          {
            if (((point.x - offset.x + tempRect.x)<0) ||  ((point.x - offset.x+ tempRect.x)>tempRect.width))//off left/right side
            {
              nsIContent* content = resultFrame->GetContent();
              if (content)
              {
                nsIContent* parent = content->GetParent();
                if (parent)
                {
                  aPos->mResultContent = parent;
                  aPos->mContentOffset = parent->IndexOf(content);
                  aPos->mAttachForward = false;
                  if ((point.x - offset.x+ tempRect.x)>tempRect.width)
                  {
                    aPos->mContentOffset++;//go to end of this frame
                    aPos->mAttachForward = true;
                  }
                  //result frame is the result frames parent.
                  aPos->mResultFrame = resultFrame->GetParent();
                  return NS_POSITION_BEFORE_TABLE;
                }
              }
            }
          }
        }

        if (!resultFrame->HasView())
        {
          nsView* view;
          nsPoint offset;
          resultFrame->GetOffsetFromView(offset, &view);
          ContentOffsets offsets =
              resultFrame->GetContentOffsetsFromPoint(point - offset);
          aPos->mResultContent = offsets.content;
          aPos->mContentOffset = offsets.offset;
          aPos->mAttachForward = offsets.associateWithNext;
          if (offsets.content)
          {
            bool selectable;
            resultFrame->IsSelectable(&selectable, nullptr);
            if (selectable)
            {
              found = true;
              break;
            }
          }
        }

        if (aPos->mDirection == eDirPrevious && (resultFrame == farStoppingFrame))
          break;
        if (aPos->mDirection == eDirNext && (resultFrame == nearStoppingFrame))
          break;
        //always try previous on THAT line if that fails go the other way
        frameTraversal->Prev();
        resultFrame = frameTraversal->CurrentItem();
        if (!resultFrame)
          return NS_ERROR_FAILURE;
      }

      if (!found){
        resultFrame = storeOldResultFrame;

        result = NS_NewFrameTraversal(getter_AddRefs(frameTraversal),
                                      aPresContext, resultFrame,
                                      eLeaf,
                                      false, // aVisual
                                      aPos->mScrollViewStop,
                                      false     // aFollowOOFs
                                      );
      }
      while ( !found ){
        nsPoint point(aPos->mDesiredX, 0);
        nsView* view;
        nsPoint offset;
        resultFrame->GetOffsetFromView(offset, &view);
        ContentOffsets offsets =
            resultFrame->GetContentOffsetsFromPoint(point - offset);
        aPos->mResultContent = offsets.content;
        aPos->mContentOffset = offsets.offset;
        aPos->mAttachForward = offsets.associateWithNext;
        if (offsets.content)
        {
          bool selectable;
          resultFrame->IsSelectable(&selectable, nullptr);
          if (selectable)
          {
            found = true;
            if (resultFrame == farStoppingFrame)
              aPos->mAttachForward = false;
            else
              aPos->mAttachForward = true;
            break;
          }
        }
        if (aPos->mDirection == eDirPrevious && (resultFrame == nearStoppingFrame))
          break;
        if (aPos->mDirection == eDirNext && (resultFrame == farStoppingFrame))
          break;
        //previous didnt work now we try "next"
        frameTraversal->Next();
        nsIFrame *tempFrame = frameTraversal->CurrentItem();
        if (!tempFrame)
          break;
        resultFrame = tempFrame;
      }
      aPos->mResultFrame = resultFrame;
    }
    else {
        //we need to jump to new block frame.
      aPos->mAmount = eSelectLine;
      aPos->mStartOffset = 0;
      aPos->mAttachForward = !(aPos->mDirection == eDirNext);
      if (aPos->mDirection == eDirPrevious)
        aPos->mStartOffset = -1;//start from end
     return aBlockFrame->PeekOffset(aPos);
    }
  }
  return NS_OK;
}

nsIFrame::CaretPosition
nsIFrame::GetExtremeCaretPosition(bool aStart)
{
  CaretPosition result;

  FrameTarget targetFrame = DrillDownToSelectionFrame(this, !aStart, 0);
  FrameContentRange range = GetRangeForFrame(targetFrame.frame);
  result.mResultContent = range.content;
  result.mContentOffset = aStart ? range.start : range.end;
  return result;
}

// Find the first (or last) descendant of the given frame
// which is either a block frame or a BRFrame.
static nsContentAndOffset
FindBlockFrameOrBR(nsIFrame* aFrame, nsDirection aDirection)
{
  nsContentAndOffset result;
  result.mContent =  nullptr;
  result.mOffset = 0;

  if (aFrame->IsGeneratedContentFrame())
    return result;

  // Treat form controls as inline leaves
  // XXX we really need a way to determine whether a frame is inline-level
  nsIFormControlFrame* fcf = do_QueryFrame(aFrame);
  if (fcf)
    return result;
  
  // Check the frame itself
  // Fall through "special" block frames because their mContent is the content
  // of the inline frames they were created from. The first/last child of
  // such frames is the real block frame we're looking for.
  if ((nsLayoutUtils::GetAsBlock(aFrame) && !(aFrame->GetStateBits() & NS_FRAME_IS_SPECIAL)) ||
      aFrame->GetType() == nsGkAtoms::brFrame) {
    nsIContent* content = aFrame->GetContent();
    result.mContent = content->GetParent();
    // In some cases (bug 310589, bug 370174) we end up here with a null content.
    // This probably shouldn't ever happen, but since it sometimes does, we want
    // to avoid crashing here.
    NS_ASSERTION(result.mContent, "Unexpected orphan content");
    if (result.mContent)
      result.mOffset = result.mContent->IndexOf(content) + 
        (aDirection == eDirPrevious ? 1 : 0);
    return result;
  }

  // If this is a preformatted text frame, see if it ends with a newline
  if (aFrame->HasTerminalNewline() &&
      aFrame->StyleText()->NewlineIsSignificant()) {
    int32_t startOffset, endOffset;
    aFrame->GetOffsets(startOffset, endOffset);
    result.mContent = aFrame->GetContent();
    result.mOffset = endOffset - (aDirection == eDirPrevious ? 0 : 1);
    return result;
  }

  // Iterate over children and call ourselves recursively
  if (aDirection == eDirPrevious) {
    nsIFrame* child = aFrame->GetLastChild(nsIFrame::kPrincipalList);
    while(child && !result.mContent) {
      result = FindBlockFrameOrBR(child, aDirection);
      child = child->GetPrevSibling();
    }
  } else { // eDirNext
    nsIFrame* child = aFrame->GetFirstPrincipalChild();
    while(child && !result.mContent) {
      result = FindBlockFrameOrBR(child, aDirection);
      child = child->GetNextSibling();
    }
  }
  return result;
}

nsresult
nsIFrame::PeekOffsetParagraph(nsPeekOffsetStruct *aPos)
{
  nsIFrame* frame = this;
  nsContentAndOffset blockFrameOrBR;
  blockFrameOrBR.mContent = nullptr;
  bool reachedBlockAncestor = false;

  // Go through containing frames until reaching a block frame.
  // In each step, search the previous (or next) siblings for the closest
  // "stop frame" (a block frame or a BRFrame).
  // If found, set it to be the selection boundray and abort.
  
  if (aPos->mDirection == eDirPrevious) {
    while (!reachedBlockAncestor) {
      nsIFrame* parent = frame->GetParent();
      // Treat a frame associated with the root content as if it were a block frame.
      if (!frame->mContent || !frame->mContent->GetParent()) {
        reachedBlockAncestor = true;
        break;
      }
      nsIFrame* sibling = frame->GetPrevSibling();
      while (sibling && !blockFrameOrBR.mContent) {
        blockFrameOrBR = FindBlockFrameOrBR(sibling, eDirPrevious);
        sibling = sibling->GetPrevSibling();
      }
      if (blockFrameOrBR.mContent) {
        aPos->mResultContent = blockFrameOrBR.mContent;
        aPos->mContentOffset = blockFrameOrBR.mOffset;
        break;
      }
      frame = parent;
      reachedBlockAncestor = (nsLayoutUtils::GetAsBlock(frame) != nullptr);
    }
    if (reachedBlockAncestor) { // no "stop frame" found
      aPos->mResultContent = frame->GetContent();
      aPos->mContentOffset = 0;
    }
  } else { // eDirNext
    while (!reachedBlockAncestor) {
      nsIFrame* parent = frame->GetParent();
      // Treat a frame associated with the root content as if it were a block frame.
      if (!frame->mContent || !frame->mContent->GetParent()) {
        reachedBlockAncestor = true;
        break;
      }
      nsIFrame* sibling = frame;
      while (sibling && !blockFrameOrBR.mContent) {
        blockFrameOrBR = FindBlockFrameOrBR(sibling, eDirNext);
        sibling = sibling->GetNextSibling();
      }
      if (blockFrameOrBR.mContent) {
        aPos->mResultContent = blockFrameOrBR.mContent;
        aPos->mContentOffset = blockFrameOrBR.mOffset;
        break;
      }
      frame = parent;
      reachedBlockAncestor = (