layout/generic/nsFrame.cpp
author Timothy Nikkel <tnikkel@gmail.com>
Mon, 12 Sep 2016 00:19:08 -0500
changeset 354778 7dc535385a4fe5286a9d91fb66f7796120bd8fb0
parent 354775 90ef23c8f05728ce678788db0b1cbf4591443097
child 354779 22b0444e1e3a2ab3be2f11822a75cc37c59d4e24
permissions -rw-r--r--
Bug 1284350. Backed out changeset 82c3b4b81d82 (Bug 1261554 (Part 2) - Mark frames which are added to the display list when painting to the window as having Visibility::IN_DISPLAYPORT. r=mstange)

/* -*- 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 "nsFrame.h"

#include <stdarg.h>
#include <algorithm>

#include "gfx2DGlue.h"
#include "gfxUtils.h"
#include "mozilla/Attributes.h"
#include "mozilla/DebugOnly.h"
#include "mozilla/gfx/2D.h"
#include "mozilla/gfx/PathHelpers.h"
#include "mozilla/Sprintf.h"

#include "nsCOMPtr.h"
#include "nsFrameList.h"
#include "nsPlaceholderFrame.h"
#include "nsIContent.h"
#include "nsIContentInlines.h"
#include "nsContentUtils.h"
#include "nsCSSPseudoElements.h"
#include "nsIAtom.h"
#include "nsString.h"
#include "nsReadableUtils.h"
#include "nsStyleContext.h"
#include "nsTableWrapperFrame.h"
#include "nsView.h"
#include "nsViewManager.h"
#include "nsIScrollableFrame.h"
#include "nsPresContext.h"
#include "nsStyleConsts.h"
#include "nsIPresShell.h"
#include "mozilla/Logging.h"
#include "mozilla/Sprintf.h"
#include "nsFrameManager.h"
#include "nsLayoutUtils.h"
#include "mozilla/RestyleManager.h"
#include "mozilla/RestyleManagerHandle.h"
#include "mozilla/RestyleManagerHandleInlines.h"

#include "nsIDOMNode.h"
#include "nsISelection.h"
#include "nsISelectionPrivate.h"
#include "nsFrameSelection.h"
#include "nsGkAtoms.h"
#include "nsHtml5Atoms.h"
#include "nsCSSAnonBoxes.h"

#include "nsFrameTraversal.h"
#include "nsRange.h"
#include "nsITextControlFrame.h"
#include "nsNameSpaceManager.h"
#include "nsIPercentBSizeObserver.h"
#include "nsStyleStructInlines.h"
#include "FrameLayerBuilder.h"
#include "ImageLayers.h"

#include "nsBidiPresUtils.h"
#include "RubyUtils.h"
#include "nsAnimationManager.h"

// For triple-click pref
#include "imgIContainer.h"
#include "imgIRequest.h"
#include "nsError.h"
#include "nsContainerFrame.h"
#include "nsBoxLayoutState.h"
#include "nsBlockFrame.h"
#include "nsDisplayList.h"
#include "nsSVGIntegrationUtils.h"
#include "nsSVGEffects.h"
#include "nsChangeHint.h"
#include "nsDeckFrame.h"
#include "nsSubDocumentFrame.h"
#include "SVGTextFrame.h"

#include "gfxContext.h"
#include "nsRenderingContext.h"
#include "nsAbsoluteContainingBlock.h"
#include "DisplayItemScrollClip.h"
#include "StickyScrollContainer.h"
#include "nsFontInflationData.h"
#include "nsRegion.h"
#include "nsIFrameInlines.h"

#include "mozilla/AsyncEventDispatcher.h"
#include "mozilla/EffectCompositor.h"
#include "mozilla/EffectSet.h"
#include "mozilla/EventListenerManager.h"
#include "mozilla/EventStateManager.h"
#include "mozilla/EventStates.h"
#include "mozilla/Preferences.h"
#include "mozilla/LookAndFeel.h"
#include "mozilla/MouseEvents.h"
#include "mozilla/css/ImageLoader.h"
#include "mozilla/gfx/Tools.h"
#include "nsPrintfCString.h"
#include "ActiveLayerTracker.h"

#include "nsITheme.h"
#include "nsThemeConstants.h"

using namespace mozilla;
using namespace mozilla::css;
using namespace mozilla::dom;
using namespace mozilla::gfx;
using namespace mozilla::layers;
using namespace mozilla::layout;
typedef nsAbsoluteContainingBlock::AbsPosReflowFlags AbsPosReflowFlags;

// 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

// This is faster than nsBidiPresUtils::IsFrameInParagraphDirection,
// because it uses the frame pointer passed in without drilling down to
// the leaf frame.
static bool
IsReversedDirectionFrame(nsIFrame* aFrame)
{
  FrameBidiData bidiData = nsBidi::GetBidiData(aFrame);
  return !IS_SAME_DIRECTION(bidiData.embeddingLevel, bidiData.baseLevel);
}

#include "nsILineIterator.h"

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

#include "prenv.h"

NS_DECLARE_FRAME_PROPERTY_DELETABLE(BoxMetricsProperty, nsBoxLayoutMetrics)

static void
InitBoxMetrics(nsIFrame* aFrame, bool aClear)
{
  FrameProperties props = aFrame->Properties();
  if (aClear) {
    props.Delete(BoxMetricsProperty());
  }

  nsBoxLayoutMetrics* metrics = new nsBoxLayoutMetrics();
  props.Set(BoxMetricsProperty(), metrics);

  static_cast<nsFrame*>(aFrame)->nsFrame::MarkIntrinsicISizesDirty();
  metrics->mBlockAscent = 0;
  metrics->mLastSize.SizeTo(0, 0);
}

static bool
IsXULBoxWrapped(const nsIFrame* aFrame)
{
  return aFrame->GetParent() &&
         aFrame->GetParent()->IsXULBoxFrame() &&
         !aFrame->IsXULBoxFrame();
}

// 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.
 */
mozilla::LazyLogModule nsFrame::sFrameLogModule("frame");

static mozilla::LazyLogModule sStyleVerifyTreeLogModuleInfo("styleverifytree");

static uint32_t gStyleVerifyTreeEnable = 0x55;

bool
nsFrame::GetVerifyStyleTreeEnable()
{
  if (gStyleVerifyTreeEnable == 0x55) {
      gStyleVerifyTreeEnable = 0 != (int)((mozilla::LogModule*)sStyleVerifyTreeLogModuleInfo)->Level();
  }
  return gStyleVerifyTreeEnable;
}

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

#endif

NS_DECLARE_FRAME_PROPERTY_DELETABLE(AbsoluteContainingBlockProperty,
                                    nsAbsoluteContainingBlock)

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 = 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
nsIFrame::ContentStatesChanged(mozilla::EventStates aStates)
{
}

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::Init(nsIFrame* aFrame)
{
  Clear(mFrame ? mFrame->PresContext()->GetPresShell() : nullptr);
  mFrame = aFrame;
  if (mFrame) {
    nsIPresShell* shell = mFrame->PresContext()->GetPresShell();
    NS_WARNING_ASSERTION(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();
#ifdef DEBUG
  mStyleContext->FrameAddRef();
#endif
}

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

  MOZ_ASSERT(!IsVisibleOrMayBecomeVisibleSoon(),
             "Visible nsFrame is being destroyed");

  NS_IF_RELEASE(mContent);
#ifdef DEBUG
  mStyleContext->FrameRelease();
#endif
  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();
  nsIAtom* frameType = aFrame->GetType();
  bool isInline = (aFrame->GetDisplay() == StyleDisplay::Inline ||
                   RubyUtils::IsRubyBox(frameType) ||
                   (aFrame->IsFloating() &&
                    frameType == 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->IsAnyOfHTMLElements(nsGkAtoms::option,
                                                             nsGkAtoms::optgroup,
                                                             nsGkAtoms::select) ||
                                content->IsInNativeAnonymousSubtree()))) &&
                  !(aFrame->IsXULBoxFrame() && aFrame->GetParent()->IsXULBoxFrame());
  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,
              nsContainerFrame* 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_PART_OF_IBSPLIT |
                       NS_FRAME_MAY_BE_TRANSFORMED |
                       NS_FRAME_MAY_HAVE_GENERATED_CONTENT |
                       NS_FRAME_CAN_HAVE_ABSPOS_CHILDREN);
  } else {
    PresContext()->ConstructedFrame();
  }
  if (GetParent()) {
    nsFrameState state = GetParent()->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 |
                       NS_FRAME_IS_NONDISPLAY);

    if (HasAnyStateBits(NS_FRAME_IN_POPUP) && TrackingVisibility()) {
      // Assume all frames in popups are visible.
      IncVisibilityCount(VisibilityCounter::IN_DISPLAYPORT);
    }
  }
  const nsStyleDisplay *disp = StyleDisplay();
  if (disp->HasTransform(this) ||
      nsLayoutUtils::HasRelevantAnimationOfProperty(this,
                                                    eCSSProperty_transform)) {
    // 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 (disp->mPosition == NS_STYLE_POSITION_STICKY &&
      !aPrevInFlow &&
      !(mState & NS_FRAME_IS_NONDISPLAY) &&
      !disp->IsInnerTableStyle()) {
    // Note that we only add first continuations, but we really only
    // want to add first continuation-or-ib-split-siblings.  But since we
    // don't yet know if we're a later part of a block-in-inline split,
    // we'll just add later members of a block-in-inline split here, and
    // then StickyScrollContainer will remove them later.
    // We don't currently support relative positioning of inner table
    // elements (bug 35168), so exclude them from sticky positioning too.
    StickyScrollContainer* ssc =
      StickyScrollContainer::GetStickyScrollContainerForFrame(this);
    if (ssc) {
      ssc->AddFrame(this);
    }
  }

  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");
  }

  if (PresContext()->PresShell()->AssumeAllFramesVisible() &&
      TrackingVisibility()) {
    IncVisibilityCount(VisibilityCounter::IN_DISPLAYPORT);
  }

  DidSetStyleContext(nullptr);

  if (::IsXULBoxWrapped(this))
    ::InitBoxMetrics(this, false);
}

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);

  if (StyleDisplay()->mPosition == NS_STYLE_POSITION_STICKY) {
    StickyScrollContainer* ssc =
      StickyScrollContainer::GetStickyScrollContainerForFrame(this);
    if (ssc) {
      ssc->RemoveFrame(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 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_PART_OF_IBSPLIT) {
    // Delete previous sibling's reference to me.
    nsIFrame* prevSib = Properties().Get(nsIFrame::IBSplitPrevSibling());
    if (prevSib) {
      NS_WARNING_ASSERTION(
        this == prevSib->Properties().Get(nsIFrame::IBSplitSibling()),
        "IB sibling chain is inconsistent");
      prevSib->Properties().Delete(nsIFrame::IBSplitSibling());
    }

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

  bool isPrimaryFrame = (mContent && mContent->GetPrimaryFrame() == this);
  if (isPrimaryFrame) {
    // This needs to happen before shell->NotifyDestroyingFrame because
    // that clears our Properties() table.
    ActiveLayerTracker::TransferActivityToContent(this, mContent);

    // Unfortunately, we need to do this for all frames being reframed
    // and not only those whose current style involves CSS transitions,
    // because what matters is whether the new style (not the old)
    // specifies CSS transitions.
    if (presContext->RestyleManager()->IsGecko()) {
      // stylo: ServoRestyleManager does not handle transitions yet, and when
      // it does it probably won't need to track reframed style contexts to
      // start transitions correctly.
      RestyleManager::ReframingStyleContexts* rsc =
        presContext->RestyleManager()->AsGecko()->GetReframingStyleContexts();
      if (rsc) {
        rsc->Put(mContent, mStyleContext);
      }
    }
  }

  if (EffectSet::GetEffectSet(this)) {
    // If no new frame for this element is created by the end of the
    // restyling process, stop animations and transitions for this frame
    if (presContext->RestyleManager()->IsGecko()) {
      RestyleManager::AnimationsWithDestroyedFrame* adf =
        presContext->RestyleManager()->AsGecko()->GetAnimationsWithDestroyedFrame();
      // AnimationsWithDestroyedFrame only lives during the restyling process.
      if (adf) {
        adf->Put(mContent, mStyleContext);
      }
    } else {
      NS_ERROR("stylo: ServoRestyleManager does not support animations yet");
    }
  }

  // Disable visibility tracking. Note that we have to do this before calling
  // NotifyDestroyingFrame(), which will clear frame properties and make us lose
  // track of whether we were previously visible or not.
  // XXX(seth): It'd be ideal to assert that we're already marked nonvisible
  // here, but it's unfortunately tricky to guarantee in the face of things like
  // frame reconstruction induced by style changes.
  DisableVisibilityTracking();

  // Ensure that we're not in the visible list anymore.
  PresContext()->GetPresShell()->MarkFrameNonvisible(this);

  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 (isPrimaryFrame) {
    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);
}

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

static
void
AddAndRemoveImageAssociations(nsFrame* aFrame,
                              const nsStyleImageLayers* aOldLayers,
                              const nsStyleImageLayers* aNewLayers)
{
   ImageLoader* imageLoader =
     aFrame->PresContext()->Document()->StyleImageLoader();

  // If the old context had a background-image image, or mask-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.)

  if (aOldLayers) {
    NS_FOR_VISIBLE_IMAGE_LAYERS_BACK_TO_FRONT(i, (*aOldLayers)) {
      // If there is an image in oldBG that's not in newBG, drop it.
      if (i >= aNewLayers->mImageCount ||
          !aOldLayers->mLayers[i].mImage.ImageDataEquals(
            aNewLayers->mLayers[i].mImage)) {
        const nsStyleImage& oldImage = aOldLayers->mLayers[i].mImage;
        if (oldImage.GetType() != eStyleImageType_Image) {
          continue;
        }

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

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

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

// Subclass hook for style post processing
/* virtual */ void
nsFrame::DidSetStyleContext(nsStyleContext* aOldStyleContext)
{
  if (IsSVGText()) {
    SVGTextFrame* svgTextFrame = static_cast<SVGTextFrame*>(
        nsLayoutUtils::GetClosestFrameOfType(this, nsGkAtoms::svgTextFrame));
    nsIFrame* anonBlock = svgTextFrame->PrincipalChildList().FirstChild();
    // Just as in SVGTextFrame::DidSetStyleContext, we need to ensure that
    // any non-display SVGTextFrames get reflowed when a child text frame
    // gets new style.
    //
    // Note that we must check NS_FRAME_FIRST_REFLOW on our SVGTextFrame's
    // anonymous block frame rather than our self, since NS_FRAME_FIRST_REFLOW
    // may be set on us if we're a new frame that has been inserted after the
    // document's first reflow. (In which case this DidSetStyleContext call may
    // be happening under frame construction under a Reflow() call.)
    if (anonBlock && !(anonBlock->GetStateBits() & NS_FRAME_FIRST_REFLOW) &&
        (svgTextFrame->GetStateBits() & NS_FRAME_IS_NONDISPLAY) &&
        !(svgTextFrame->GetStateBits() & NS_STATE_SVG_TEXT_IN_REFLOW)) {
      svgTextFrame->ScheduleReflowSVGNonDisplayText(nsIPresShell::eStyleChange);
    }
  }

  const nsStyleImageLayers *oldLayers = aOldStyleContext ?
                              &aOldStyleContext->StyleBackground()->mImage :
                              nullptr;
  const nsStyleImageLayers *newLayers = &StyleBackground()->mImage;
  AddAndRemoveImageAssociations(this, oldLayers, newLayers);

  oldLayers = aOldStyleContext ? &aOldStyleContext->StyleSVGReset()->mMask :
                                  nullptr;
  newLayers = &StyleSVGReset()->mMask;
  AddAndRemoveImageAssociations(this, oldLayers, newLayers);

  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));
      }
    }
  }

  ImageLoader* imageLoader = PresContext()->Document()->StyleImageLoader();
  imgIRequest *oldBorderImage = aOldStyleContext
    ? aOldStyleContext->StyleBorder()->GetBorderImageRequest()
    : nullptr;
  imgIRequest *newBorderImage = StyleBorder()->GetBorderImageRequest();
  // 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 (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();
  }

  RemoveStateBits(NS_FRAME_SIMPLE_EVENT_REGIONS);
}

// 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 = Properties().Get(UsedMarginProperty());
  if (m) {
    margin = *m;
  } else {
    if (!StyleMargin()->GetMargin(margin)) {
      // If we get here, our caller probably shouldn't be calling us...
      NS_ERROR("Returning bogus 0-sized margin, because this margin "
               "depends on layout & isn't cached!");
    }
  }
  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 = 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 = Properties().Get(UsedPaddingProperty());
  if (p) {
    padding = *p;
  } else {
    if (!StylePadding()->GetPadding(padding)) {
      // If we get here, our caller probably shouldn't be calling us...
      NS_ERROR("Returning bogus 0-sized padding, because this padding "
               "depends on layout & isn't cached!");
    }
  }
  return padding;
}

nsIFrame::Sides
nsIFrame::GetSkipSides(const ReflowInput* aReflowInput) const
{
  if (MOZ_UNLIKELY(StyleBorder()->mBoxDecorationBreak ==
                     StyleBoxDecorationBreak::Clone) &&
      !(GetStateBits() & NS_FRAME_IS_OVERFLOW_CONTAINER)) {
    return Sides();
  }

  // Convert the logical skip sides to physical sides using the frame's
  // writing mode
  WritingMode writingMode = GetWritingMode();
  LogicalSides logicalSkip = GetLogicalSkipSides(aReflowInput);
  Sides skip;

  if (logicalSkip.BStart()) {
    if (writingMode.IsVertical()) {
      skip |= writingMode.IsVerticalLR() ? eSideBitsLeft : eSideBitsRight;
    } else {
      skip |= eSideBitsTop;
    }
  }

  if (logicalSkip.BEnd()) {
    if (writingMode.IsVertical()) {
      skip |= writingMode.IsVerticalLR() ? eSideBitsRight : eSideBitsLeft;
    } else {
      skip |= eSideBitsBottom;
    }
  }

  if (logicalSkip.IStart()) {
    if (writingMode.IsVertical()) {
      skip |= eSideBitsTop;
    } else {
      skip |= writingMode.IsBidiLTR() ? eSideBitsLeft : eSideBitsRight;
    }
  }

  if (logicalSkip.IEnd()) {
    if (writingMode.IsVertical()) {
      skip |= eSideBitsBottom;
    } else {
      skip |= writingMode.IsBidiLTR() ? eSideBitsRight : eSideBitsLeft;
    }
  }
  return skip;
}

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

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

WritingMode
nsIFrame::GetWritingMode(nsIFrame* aSubFrame) const
{
  WritingMode writingMode = GetWritingMode();

  if (!writingMode.IsVertical() &&
      (StyleTextReset()->mUnicodeBidi & NS_STYLE_UNICODE_BIDI_PLAINTEXT)) {
    nsBidiLevel frameLevel = nsBidiPresUtils::GetFrameBaseLevel(aSubFrame);
    writingMode.SetDirectionFromBidiLevel(frameLevel);
  }

  return writingMode;
}

nsRect
nsIFrame::GetMarginRectRelativeToSelf() const
{
  nsMargin m = GetUsedMargin();
  m.ApplySkipSides(GetSkipSides());
  nsRect r(0, 0, mRect.width, mRect.height);
  r.Inflate(m);
  return r;
}

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

bool
nsIFrame::HasOpacityInternal(float aThreshold) const
{
  MOZ_ASSERT(0.0 <= aThreshold && aThreshold <= 1.0, "Invalid argument");
  return StyleEffects()->mOpacity < aThreshold ||
         (StyleDisplay()->mWillChangeBitField & NS_STYLE_WILL_CHANGE_OPACITY) ||
         (mContent &&
           nsLayoutUtils::HasRelevantAnimationOfProperty(
             this, eCSSProperty_opacity) &&
           mContent->GetPrimaryFrame() == this);
}

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

bool
nsIFrame::Extend3DContext() const
{
  const nsStyleDisplay* disp = StyleDisplay();
  if (disp->mTransformStyle != NS_STYLE_TRANSFORM_STYLE_PRESERVE_3D ||
      !IsFrameOfType(nsIFrame::eSupportsCSSTransforms)) {
    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;
  }

  if (HasOpacity()) {
    return false;
  }

  const nsStyleEffects* effects = StyleEffects();
  return !nsFrame::ShouldApplyOverflowClipping(this, disp) &&
         !GetClipPropClipRect(disp, effects, GetSize()) &&
         !nsSVGIntegrationUtils::UsingEffectsForFrame(this);
}

bool
nsIFrame::Combines3DTransformWithAncestors() const
{
  if (!GetParent() || !GetParent()->Extend3DContext()) {
    return false;
  }
  return StyleDisplay()->HasTransform(this) || BackfaceIsHidden();
}

bool
nsIFrame::In3DContextAndBackfaceIsHidden() const
{
  return Combines3DTransformWithAncestors() && BackfaceIsHidden();
}

bool
nsIFrame::HasPerspective() const
{
  if (!IsTransformed()) {
    return false;
  }
  nsIFrame* containingBlock = GetContainingBlock(SKIP_SCROLLED_FRAME);
  if (!containingBlock) {
    return false;
  }
  return containingBlock->ChildrenHavePerspective();
}

bool
nsIFrame::ChildrenHavePerspective() const
{
  return StyleDisplay()->HasPerspectiveStyle();
}

nsRect
nsIFrame::GetContentRectRelativeToSelf() const
{
  nsMargin bp(GetUsedBorderAndPadding());
  bp.ApplySkipSides(GetSkipSides());
  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,
                             Sides 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.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.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.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.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(const nsSize& aFrameSize, const nsSize& aBorderArea,
                         Sides aSkipSides, 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;
  }
  return ComputeBorderRadii(StyleBorder()->mBorderRadius,
                            aFrameSize, aBorderArea,
                            aSkipSides, aRadii);
}

bool
nsIFrame::GetBorderRadii(nscoord aRadii[8]) const
{
  nsSize sz = GetSize();
  return GetBorderRadii(sz, sz, 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::GetLogicalBaseline(WritingMode aWritingMode) const
{
  NS_ASSERTION(!NS_SUBTREE_DIRTY(this),
               "frame must not be dirty");
  // Baseline for inverted line content is the top (block-start) margin edge,
  // as the frame is in effect "flipped" for alignment purposes.
  if (aWritingMode.IsLineInverted()) {
    return -GetLogicalUsedMargin(aWritingMode).BStart(aWritingMode);
  }
  // Otherwise, the bottom margin edge, per CSS2.1's definition of the
  // 'baseline' value of 'vertical-align'.
  return BSize(aWritingMode) +
         GetLogicalUsedMargin(aWritingMode).BEnd(aWritingMode);
}

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 Visibility
VisibilityStateAsVisibility(const nsIFrame::VisibilityState& aState)
{
  if (aState.mInDisplayPortCounter > 0) {
    return Visibility::IN_DISPLAYPORT;  // Takes priority over MAY_BECOME_VISIBLE.
  }
  if (aState.mApproximateCounter > 0) {
    return Visibility::MAY_BECOME_VISIBLE;
  }
  return Visibility::NONVISIBLE;
}

Visibility
nsIFrame::GetVisibility() const
{
  if (!(GetStateBits() & NS_FRAME_VISIBILITY_IS_TRACKED)) {
    return Visibility::UNTRACKED;
  }

  bool isSet = false;
  FrameProperties props = Properties();
  VisibilityState state = props.Get(VisibilityStateProperty(), &isSet);

  MOZ_ASSERT(isSet, "Should have a VisibilityStateProperty value "
                    "if NS_FRAME_VISIBILITY_IS_TRACKED is set");

  return VisibilityStateAsVisibility(state);
}

void
nsIFrame::UpdateVisibilitySynchronously()
{
  nsIPresShell* presShell = PresContext()->PresShell();
  if (!presShell) {
    return;
  }

  if (presShell->AssumeAllFramesVisible()) {
    presShell->MarkFrameVisibleInDisplayPort(this);
    return;
  }

  bool visible = true;
  nsIFrame* f = GetParent();
  nsRect rect = GetRectRelativeToSelf();
  nsIFrame* rectFrame = this;
  while (f) {
    nsIScrollableFrame* sf = do_QueryFrame(f);
    if (sf) {
      nsRect transformedRect =
        nsLayoutUtils::TransformFrameRectToAncestor(rectFrame, rect, f);
      if (!sf->IsRectNearlyVisible(transformedRect)) {
        visible = false;
        break;
      }

      // In this code we're trying to synchronously update *approximate*
      // visibility. (In the future we may update precise visibility here as
      // well, which is why the method name does not contain 'approximate'.) The
      // IsRectNearlyVisible() check above tells us that the rect we're checking
      // is approximately visible within the scrollframe, but we still need to
      // ensure that, even if it was scrolled into view, it'd be visible when we
      // consider the rest of the document. To do that, we move transformedRect
      // to be contained in the scrollport as best we can (it might not fit) to
      // pretend that it was scrolled into view.
      rect = transformedRect.MoveInsideAndClamp(sf->GetScrollPortRect());
      rectFrame = f;
    }
    nsIFrame* parent = f->GetParent();
    if (!parent) {
      parent = nsLayoutUtils::GetCrossDocParentFrame(f);
      if (parent && parent->PresContext()->IsChrome()) {
        break;
      }
    }
    f = parent;
  }

  if (visible) {
    presShell->MarkFrameVisibleInDisplayPort(this);
  } else {
    presShell->MarkFrameNonvisible(this);
  }
}

void
nsIFrame::EnableVisibilityTracking()
{
  if (GetStateBits() & NS_FRAME_VISIBILITY_IS_TRACKED) {
    return;  // Nothing to do.
  }

  FrameProperties props = Properties();
  MOZ_ASSERT(!props.Has(VisibilityStateProperty()),
             "Shouldn't have a VisibilityStateProperty value "
             "if NS_FRAME_VISIBILITY_IS_TRACKED is not set");

  // Add the state bit so we know to track visibility for this frame, and
  // initialize the frame property.
  AddStateBits(NS_FRAME_VISIBILITY_IS_TRACKED);
  props.Set(VisibilityStateProperty(), VisibilityState{0, 0});

  nsIPresShell* presShell = PresContext()->PresShell();
  if (!presShell) {
    return;
  }

  // Schedule a visibility update. This method will virtually always be called
  // when layout has changed anyway, so it's very unlikely that any additional
  // visibility updates will be triggered by this, but this way we guarantee
  // that if this frame is currently visible we'll eventually find out.
  presShell->ScheduleApproximateFrameVisibilityUpdateSoon();
}

void
nsIFrame::DisableVisibilityTracking()
{
  if (!(GetStateBits() & NS_FRAME_VISIBILITY_IS_TRACKED)) {
    return;  // Nothing to do.
  }

  bool isSet = false;
  FrameProperties props = Properties();
  VisibilityState state = props.Remove(VisibilityStateProperty(), &isSet);

  MOZ_ASSERT(isSet, "Should have a VisibilityStateProperty value "
                    "if NS_FRAME_VISIBILITY_IS_TRACKED is set");

  RemoveStateBits(NS_FRAME_VISIBILITY_IS_TRACKED);

  Visibility previousVisibility = VisibilityStateAsVisibility(state);
  if (previousVisibility == Visibility::NONVISIBLE) {
    return;  // We were already nonvisible.
  }

  // We were visible, so send an OnVisibilityChange() notification.
  OnVisibilityChange(Visibility::NONVISIBLE);
}

void
nsIFrame::DecVisibilityCount(VisibilityCounter aCounter,
                             Maybe<OnNonvisible> aNonvisibleAction /* = Nothing() */)
{
  MOZ_ASSERT(GetStateBits() & NS_FRAME_VISIBILITY_IS_TRACKED);

  bool isSet = false;
  FrameProperties props = Properties();
  VisibilityState state = props.Get(VisibilityStateProperty(), &isSet);

  MOZ_ASSERT(isSet, "Should have a VisibilityStateProperty value "
                    "if NS_FRAME_VISIBILITY_IS_TRACKED is set");
  MOZ_ASSERT_IF(aCounter == VisibilityCounter::MAY_BECOME_VISIBLE,
                state.mApproximateCounter > 0);
  MOZ_ASSERT_IF(aCounter == VisibilityCounter::IN_DISPLAYPORT,
                state.mInDisplayPortCounter > 0);

  Visibility previousVisibility = VisibilityStateAsVisibility(state);

  if (aCounter == VisibilityCounter::MAY_BECOME_VISIBLE) {
    state.mApproximateCounter--;
  } else {
    state.mInDisplayPortCounter--;
  }

  props.Set(VisibilityStateProperty(), state);

  Visibility newVisibility = VisibilityStateAsVisibility(state);
  if (newVisibility == previousVisibility) {
    return;  // Nothing changed.
  }

  // Our visibility just changed, so send an OnVisibilityChange() notification.
  OnVisibilityChange(newVisibility, aNonvisibleAction);
}

void
nsIFrame::IncVisibilityCount(VisibilityCounter aCounter)
{
  MOZ_ASSERT(GetStateBits() & NS_FRAME_VISIBILITY_IS_TRACKED);

  bool isSet = false;
  FrameProperties props = Properties();
  VisibilityState state = props.Get(VisibilityStateProperty(), &isSet);

  MOZ_ASSERT(isSet, "Should have a VisibilityStateProperty value "
                    "if NS_FRAME_VISIBILITY_IS_TRACKED is set");

  Visibility previousVisibility = VisibilityStateAsVisibility(state);

  if (aCounter == VisibilityCounter::MAY_BECOME_VISIBLE) {
    state.mApproximateCounter++;
  } else {
    state.mInDisplayPortCounter++;
  }

  props.Set(VisibilityStateProperty(), state);

  Visibility newVisibility = VisibilityStateAsVisibility(state);
  if (newVisibility == previousVisibility) {
    return;  // Nothing changed.
  }

  // Our visibility just changed, so send an OnVisibilityChange() notification.
  OnVisibilityChange(newVisibility);
}

void
nsIFrame::OnVisibilityChange(Visibility aNewVisibility,
                             Maybe<OnNonvisible> aNonvisibleAction
                               /* = Nothing() */)
{
  // XXX(seth): In bug 1218990 we'll implement visibility tracking for CSS
  // images here.
}

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) override;
  NS_DISPLAY_DECL_NAME("SelectionOverlay", TYPE_SELECTION_OVERLAY)
private:
  int16_t mSelectionValue;
};

void nsDisplaySelectionOverlay::Paint(nsDisplayListBuilder* aBuilder,
                                      nsRenderingContext* aCtx)
{
  DrawTarget& aDrawTarget = *aCtx->GetDrawTarget();

  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;
  }

  Color c = Color::FromABGR(LookAndFeel::GetColor(colorID, NS_RGB(255, 255, 255)));
  c.a = .5;
  ColorPattern color(ToDeviceColor(c));

  nsIntRect pxRect =
    mVisibleRect.ToOutsidePixels(mFrame->PresContext()->AppUnitsPerDevPixel());
  Rect rect(pxRect.x, pxRect.y, pxRect.width, pxRect.height);
  MaybeSnapToDevicePixels(rect, aDrawTarget, true);

  aDrawTarget.FillRect(rect, color);
}

/********************************************************
* 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->mSelectionType == SelectionType::eNormal) {
      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));
}

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

bool
nsFrame::DisplayBackgroundUnconditional(nsDisplayListBuilder* aBuilder,
                                        const nsDisplayListSet& aLists,
                                        bool aForceBackground)
{
  // 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) {
    return nsDisplayBackgroundImage::AppendBackgroundItemsToTop(
        aBuilder, this, GetRectRelativeToSelf(), aLists.BorderBackground());
  }
  return false;
}

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

  bool bgIsThemed = DisplayBackgroundUnconditional(aBuilder, aLists,
                                                   aForceBackground);

  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 (!bgIsThemed && 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.
  return (aFrame->GetStateBits() & NS_FRAME_SVG_LAYOUT) &&
          aFrame->GetContent()->IsAnyOfSVGElements(nsGkAtoms::svg,
                                                   nsGkAtoms::foreignObject);
}

Maybe<nsRect>
nsIFrame::GetClipPropClipRect(const nsStyleDisplay* aDisp,
                              const nsStyleEffects* aEffects,
                              const nsSize& aSize) const
{
  if (!(aEffects->mClipFlags & NS_STYLE_CLIP_RECT) ||
      !(aDisp->IsAbsolutelyPositioned(this) || IsSVGContentWithCSSClip(this))) {
    return Nothing();
  }

  nsRect rect = aEffects->mClip;
  if (MOZ_LIKELY(StyleBorder()->mBoxDecorationBreak ==
                   StyleBoxDecorationBreak::Slice)) {
    // The clip applies to the joined boxes so it's relative the first
    // continuation.
    nscoord y = 0;
    for (nsIFrame* f = GetPrevContinuation(); f; f = f->GetPrevContinuation()) {
      y += f->GetRect().height;
    }
    rect.MoveBy(nsPoint(0, -y));
  }

  if (NS_STYLE_CLIP_RIGHT_AUTO & aEffects->mClipFlags) {
    rect.width = aSize.width - rect.x;
  }
  if (NS_STYLE_CLIP_BOTTOM_AUTO & aEffects->mClipFlags) {
    rect.height = aSize.height - rect.y;
  }
  return Some(rect);
}

/**
 * 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 clipRect;
  bool haveRadii = false;
  nscoord radii[8];
  if (aFrame->StyleDisplay()->mOverflowClipBox ==
        NS_STYLE_OVERFLOW_CLIP_BOX_PADDING_BOX) {
    clipRect = aFrame->GetPaddingRectRelativeToSelf() +
      aBuilder->ToReferenceFrame(aFrame);
    haveRadii = aFrame->GetPaddingBoxBorderRadii(radii);
  } else {
    clipRect = aFrame->GetContentRectRelativeToSelf() +
      aBuilder->ToReferenceFrame(aFrame);
    // XXX border-radius
  }
  aClipState.ClipContainingBlockDescendantsExtra(clipRect, haveRadii ? radii : nullptr);
}

#ifdef DEBUG
static void PaintDebugBorder(nsIFrame* aFrame, DrawTarget* aDrawTarget,
     const nsRect& aDirtyRect, nsPoint aPt)
{
  nsRect r(aPt, aFrame->GetSize());
  int32_t appUnitsPerDevPixel = aFrame->PresContext()->AppUnitsPerDevPixel();
  Color blueOrRed(aFrame->HasView() ? Color(0.f, 0.f, 1.f, 1.f) :
                                      Color(1.f, 0.f, 0.f, 1.f));
  aDrawTarget->StrokeRect(NSRectToRect(r, appUnitsPerDevPixel),
                          ColorPattern(ToDeviceColor(blueOrRed)));
}

static void PaintEventTargetBorder(nsIFrame* aFrame, DrawTarget* aDrawTarget,
     const nsRect& aDirtyRect, nsPoint aPt)
{
  nsRect r(aPt, aFrame->GetSize());
  int32_t appUnitsPerDevPixel = aFrame->PresContext()->AppUnitsPerDevPixel();
  ColorPattern purple(ToDeviceColor(Color(.5f, 0.f, .5f, 1.f)));
  aDrawTarget->StrokeRect(NSRectToRect(r, appUnitsPerDevPixel), purple);
}

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 bool
IsScrollFrameActive(nsDisplayListBuilder* aBuilder, nsIScrollableFrame* aScrollableFrame)
{
  return aScrollableFrame && aScrollableFrame->IsScrollingActive(aBuilder);
}

class AutoSaveRestoreContainsBlendMode
{
  nsDisplayListBuilder& mBuilder;
  bool mSavedContainsBlendMode;
public:
  explicit AutoSaveRestoreContainsBlendMode(nsDisplayListBuilder& aBuilder)
    : mBuilder(aBuilder)
    , mSavedContainsBlendMode(aBuilder.ContainsBlendMode())
  { }

  ~AutoSaveRestoreContainsBlendMode() {
    mBuilder.SetContainsBlendMode(mSavedContainsBlendMode);
  }
};

static void
CheckForApzAwareEventHandlers(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame)
{
  nsIContent* content = aFrame->GetContent();
  if (!content) {
    return;
  }

  if (content->IsNodeApzAware()) {
    aBuilder->SetAncestorHasApzAwareEventHandler(true);
  }
}

/**
 * True if aDescendant participates the context aAncestor participating.
 */
static bool
FrameParticipatesIn3DContext(nsIFrame* aAncestor, nsIFrame* aDescendant) {
  MOZ_ASSERT(aAncestor != aDescendant);
  MOZ_ASSERT(aAncestor->Extend3DContext());
  nsIFrame* frame;
  for (frame = nsLayoutUtils::GetCrossDocParentFrame(aDescendant);
       frame && aAncestor != frame;
       frame = nsLayoutUtils::GetCrossDocParentFrame(frame)) {
    if (!frame->Extend3DContext()) {
      return false;
    }
  }
  MOZ_ASSERT(frame == aAncestor);
  return true;
}

static bool
ItemParticipatesIn3DContext(nsIFrame* aAncestor, nsDisplayItem* aItem)
{
  nsIFrame* transformFrame;
  if (aItem->GetType() == nsDisplayItem::TYPE_TRANSFORM) {
    transformFrame = aItem->Frame();
  } else if (aItem->GetType() == nsDisplayItem::TYPE_PERSPECTIVE) {
    transformFrame = static_cast<nsDisplayPerspective*>(aItem)->TransformFrame();
  } else {
    return false;
  }
  if (aAncestor == transformFrame) {
    return true;
  }
  return FrameParticipatesIn3DContext(aAncestor, transformFrame);
}

static void
WrapSeparatorTransform(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
                       nsRect& aDirtyRect,
                       nsDisplayList* aSource, nsDisplayList* aTarget,
                       int aIndex) {
  if (!aSource->IsEmpty()) {
    nsDisplayTransform *sepIdItem =
      new (aBuilder) nsDisplayTransform(aBuilder, aFrame, aSource,
                                        aDirtyRect, Matrix4x4(), aIndex);
    sepIdItem->SetNoExtendContext();
    aTarget->AppendToTop(sepIdItem);
  }
}

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();
  const nsStyleEffects* effects = StyleEffects();
  // 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.
  bool needEventRegions =
    aBuilder->IsBuildingLayerEventRegions() &&
    StyleUserInterface()->GetEffectivePointerEvents(this) !=
      NS_STYLE_POINTER_EVENTS_NONE;
  bool opacityItemForEventsAndPluginsOnly = false;
  if (effects->mOpacity == 0.0 && aBuilder->IsForPainting() &&
      !(disp->mWillChangeBitField & NS_STYLE_WILL_CHANGE_OPACITY) &&
      !nsLayoutUtils::HasCurrentAnimationOfProperty(this,
                                                    eCSSProperty_opacity)) {
    if (needEventRegions ||
        aBuilder->WillComputePluginGeometry()) {
      opacityItemForEventsAndPluginsOnly = true;
    } else {
      return;
    }
  }

  if (disp->mWillChangeBitField != 0) {
    aBuilder->AddToWillChangeBudget(this, GetSize());
  }

  bool extend3DContext = Extend3DContext();
  Maybe<nsDisplayListBuilder::AutoPreserves3DContext> autoPreserves3DContext;
  if (extend3DContext && !Combines3DTransformWithAncestors()) {
    // Start a new preserves3d context to keep informations on
    // nsDisplayListBuilder.
    autoPreserves3DContext.emplace(aBuilder);
    // Save dirty rect on the builder to avoid being distorted for
    // multiple transforms along the chain.
    aBuilder->SetPreserves3DDirtyRect(aDirtyRect);
  }

  // For preserves3d, use the dirty rect already installed on the
  // builder, since aDirtyRect maybe distorted for transforms along
  // the chain.
  nsRect dirtyRect = aDirtyRect;

  bool inTransform = aBuilder->IsInTransform();
  bool isTransformed = IsTransformed();
  bool hasPerspective = HasPerspective();
  // reset blend mode so we can keep track if this stacking context needs have
  // a nsDisplayBlendContainer. Set the blend mode back when the routine exits
  // so we keep track if the parent stacking context needs a container too.
  AutoSaveRestoreContainsBlendMode autoRestoreBlendMode(*aBuilder);
  aBuilder->SetContainsBlendMode(false);
 
  nsRect dirtyRectOutsideTransform = dirtyRect;
  if (isTransformed) {
    const nsRect overflow = GetVisualOverflowRectRelativeToSelf();
    if (nsDisplayTransform::ShouldPrerenderTransformedContent(aBuilder,
                                                              this)) {
      dirtyRect = overflow;
    } else {
      if (overflow.IsEmpty() && !extend3DContext) {
        return;
      }

      // If we're in preserve-3d then grab the dirty rect that was given to the root
      // and transform using the combined transform.
      if (Combines3DTransformWithAncestors()) {
        dirtyRect = aBuilder->GetPreserves3DDirtyRect(this);
      }

      nsRect untransformedDirtyRect;
      if (nsDisplayTransform::UntransformRect(dirtyRect, overflow, this,
            &untransformedDirtyRect)) {
        dirtyRect = untransformedDirtyRect;
      } else {
        NS_WARNING("Unable to untransform dirty rect!");
        // This should only happen if the transform is singular, in which case nothing is visible anyway
        dirtyRect.SetEmpty();
      }
    }
    inTransform = true;
  }

  bool usingSVGEffects = nsSVGIntegrationUtils::UsingEffectsForFrame(this);
  nsRect dirtyRectOutsideSVGEffects = dirtyRect;
  nsDisplayList hoistedScrollInfoItemsStorage;
  if (usingSVGEffects) {
    dirtyRect =
      nsSVGIntegrationUtils::GetRequiredSourceForInvalidArea(this, dirtyRect);
    aBuilder->EnterSVGEffectsContents(&hoistedScrollInfoItemsStorage);
  }

  // We build an opacity item if it's not going to be drawn by SVG content, or
  // SVG effects. SVG effects won't handle the opacity if we want an active
  // layer (for async animations), see
  // nsSVGIntegrationsUtils::PaintMaskAndClipPath or
  // nsSVGIntegrationsUtils::PaintFilter.
  bool useOpacity = HasVisualOpacity() && !nsSVGUtils::CanOptimizeOpacity(this) &&
                    (!usingSVGEffects || nsDisplayOpacity::NeedsActiveLayer(aBuilder, this));
  bool useBlendMode = effects->mMixBlendMode != NS_STYLE_BLEND_NORMAL;
  bool useStickyPosition = disp->mPosition == NS_STYLE_POSITION_STICKY &&
    IsScrollFrameActive(aBuilder,
                        nsLayoutUtils::GetNearestScrollableFrame(GetParent(),
                        nsLayoutUtils::SCROLLABLE_SAME_DOC |
                        nsLayoutUtils::SCROLLABLE_INCLUDE_HIDDEN));
  bool useFixedPosition = nsLayoutUtils::IsFixedPosFrameInDisplayPort(this);

  nsDisplayListBuilder::AutoBuildingDisplayList
    buildingDisplayList(aBuilder, this, dirtyRect, true);

  // Depending on the effects that are applied to this frame, we can create
  // multiple container display items and wrap them around our contents.
  // This enum lists all the potential container display items, in the order
  // outside to inside.
  enum class ContainerItemType : uint8_t {
    eNone = 0,
    eOwnLayerIfNeeded,
    eBlendMode,
    eFixedPosition,
    eStickyPosition,
    eOwnLayerForTransformWithRoundedClip,
    ePerspective,
    eTransform,
    eSeparatorTransforms,
    eOpacity,
    eSVGEffects,
    eBlendContainer
  };

  DisplayListClipState::AutoSaveRestore clipState(aBuilder);

  // If there is a current clip, then depending on the container items we
  // create, different things can happen to it. Some container items simply
  // propagate the clip to their children and aren't clipped themselves.
  // But other container items, especially those that establish a different
  // geometry for their contents (e.g. transforms), capture the clip on
  // themselves and unset the clip for their contents. If we create more than
  // one of those container items, the clip will be captured on the outermost
  // one and the inner container items will be unclipped.
  ContainerItemType clipCapturedBy = ContainerItemType::eNone;
  if (useFixedPosition) {
    clipCapturedBy = ContainerItemType::eFixedPosition;
  } else if (useStickyPosition) {
    clipCapturedBy = ContainerItemType::eStickyPosition;
  } else if (isTransformed) {
    if ((hasPerspective || extend3DContext) && clipState.SavedStateHasRoundedCorners()) {
      // If we're creating an nsDisplayTransform item that is going to combine
      // its transform with its children (preserve-3d or perspective), then we
      // can't have an intermediate surface. Mask layers force an intermediate
      // surface, so if we're going to need both then create a separate
      // wrapping layer for the mask.
      clipCapturedBy = ContainerItemType::eOwnLayerForTransformWithRoundedClip;
    } else if (hasPerspective) {
      clipCapturedBy = ContainerItemType::ePerspective;
    } else {
      clipCapturedBy = ContainerItemType::eTransform;
    }
  } else if (usingSVGEffects) {
    clipCapturedBy = ContainerItemType::eSVGEffects;
  }

  bool clearClip = false;
  if (clipCapturedBy != ContainerItemType::eNone) {
    // 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.
    clearClip = true;
  }

  clipState.EnterStackingContextContents(clearClip);

  nsDisplayListCollection set;
  {
    DisplayListClipState::AutoSaveRestore nestedClipState(aBuilder);
    nsDisplayListBuilder::AutoInTransformSetter
      inTransformSetter(aBuilder, inTransform);
    nsDisplayListBuilder::AutoSaveRestorePerspectiveIndex
      perspectiveIndex(aBuilder, this);

    CheckForApzAwareEventHandlers(aBuilder, this);

    Maybe<nsRect> clipPropClip = GetClipPropClipRect(disp, effects, GetSize());
    if (clipPropClip) {
      dirtyRect.IntersectRect(dirtyRect, *clipPropClip);
      nestedClipState.ClipContentDescendants(
        *clipPropClip + aBuilder->ToReferenceFrame(this));
    }

    // extend3DContext 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 (extend3DContext) {
      // Mark these first so MarkAbsoluteFramesForDisplayList knows if we are
      // going to be forced to descend into frames.
      aBuilder->MarkPreserve3DFramesForDisplayList(this);
    }

    MarkAbsoluteFramesForDisplayList(aBuilder, dirtyRect);

    nsDisplayLayerEventRegions* eventRegions = nullptr;
    if (aBuilder->IsBuildingLayerEventRegions()) {
      eventRegions = new (aBuilder) nsDisplayLayerEventRegions(aBuilder, this);
      eventRegions->AddFrame(aBuilder, this);
      aBuilder->SetLayerEventRegions(eventRegions);
    }
    aBuilder->AdjustWindowDraggingRegion(this);
    BuildDisplayList(aBuilder, dirtyRect, set);
    if (eventRegions) {
      // If the event regions item ended up empty, throw it away rather than
      // adding it to the display list.
      if (!eventRegions->IsEmpty()) {
        set.BorderBackground()->AppendToBottom(eventRegions);
      } else {
        aBuilder->SetLayerEventRegions(nullptr);
        eventRegions->~nsDisplayLayerEventRegions();
        eventRegions = nullptr;
      }
    }
  }

  if (aBuilder->IsBackgroundOnly()) {
    set.BlockBorderBackgrounds()->DeleteAll();
    set.Floats()->DeleteAll();
    set.Content()->DeleteAll();
    set.PositionedDescendants()->DeleteAll();
    set.Outlines()->DeleteAll();
  }

  // Sort PositionedDescendants() in CSS 'z-order' order.  The list is already
  // in content document order and SortByZOrder is a stable sort which
  // guarantees 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();

  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 && item->ZIndex() < 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(content);
  }
#ifdef DEBUG
  DisplayDebugBorders(aBuilder, this, set);
#endif
  resultList.AppendToTop(set.Outlines());
  // 8, 9: non-negative z-index children
  resultList.AppendToTop(set.PositionedDescendants());

  // Get the scroll clip to use for the container items that we create here.
  // If we cleared the clip, and we create multiple container items, then the
  // items we create before we restore the clip will have a different scroll
  // clip from the items we create after we restore the clip.
  const DisplayItemScrollClip* containerItemScrollClip =
    aBuilder->ClipState().CurrentAncestorScrollClipForStackingContextContents();

  /* If adding both a nsDisplayBlendContainer and a nsDisplayBlendMode to the
   * same list, the nsDisplayBlendContainer should be added first. This only
   * happens when the element creating this stacking context has mix-blend-mode
   * and also contains a child which has mix-blend-mode.
   * The nsDisplayBlendContainer must be added to the list first, so it does not
   * isolate the containing element blending as well.
   */

  if (aBuilder->ContainsBlendMode()) {
    DisplayListClipState::AutoSaveRestore blendContainerClipState(aBuilder);
    blendContainerClipState.Clear();
    resultList.AppendNewToTop(
      nsDisplayBlendContainer::CreateForMixBlendMode(aBuilder, this, &resultList,
                                                     containerItemScrollClip));
  }

  /* 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) {
    MOZ_ASSERT(StyleEffects()->HasFilters() ||
               nsSVGIntegrationUtils::UsingMaskOrClipPathForFrame(this),
               "Beside filter & mask/clip-path, what else effect do we have?");

    if (clipCapturedBy == ContainerItemType::eSVGEffects) {
      clipState.ExitStackingContextContents(&containerItemScrollClip);
    }
    // Revert to the post-filter dirty rect.
    buildingDisplayList.SetDirtyRect(dirtyRectOutsideSVGEffects);

    // Skip all filter effects while generating glyph mask.
    bool createFilter =
      StyleEffects()->HasFilters() && !aBuilder->IsForGenerateGlyphMask();
    bool createMask = nsSVGIntegrationUtils::UsingMaskOrClipPathForFrame(this);

    if (createFilter) {
      // If we are going to create a mask display item, handle opacity effect
      // in that mask display item; Otherwise, take care of opacity in this
      // filter display item.
      bool handleOpacity = !createMask && !useOpacity;

      /* List now emptied, so add the new list to the top. */
      resultList.AppendNewToTop(
        new (aBuilder) nsDisplayFilter(aBuilder, this, &resultList,
                                       handleOpacity));
    }

    if (createMask) {
      /* List now emptied, so add the new list to the top. */
      resultList.AppendNewToTop(
          new (aBuilder) nsDisplayMask(aBuilder, this, &resultList,
                                       !useOpacity));
    }

    // Also add the hoisted scroll info items. We need those for APZ scrolling
    // because nsDisplayMask items can't build active layers.
    aBuilder->ExitSVGEffectsContents();
    resultList.AppendToTop(&hoistedScrollInfoItemsStorage);
  }

  /* If the list is non-empty and there is CSS group opacity without SVG
   * effects, wrap it up in an opacity item.
   */
  if (useOpacity && !resultList.IsEmpty()) {
    // Don't clip nsDisplayOpacity items. We clip their descendants instead.
    // The clip we would set on an element with opacity would clip
    // all descendant content, but some should not be clipped.
    DisplayListClipState::AutoSaveRestore opacityClipState(aBuilder);
    opacityClipState.Clear();
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplayOpacity(aBuilder, this, &resultList,
                                        containerItemScrollClip, opacityItemForEventsAndPluginsOnly));
  }

  /* 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, so that we find all the
   * correct children.
   */
  if (isTransformed && !resultList.IsEmpty() && extend3DContext) {
    // Install dummy nsDisplayTransform as a leaf containing
    // descendants not participating this 3D rendering context.
    nsDisplayList nonparticipants;
    nsDisplayList participants;
    int index = 1;

    while (nsDisplayItem* item = resultList.RemoveBottom()) {
      if (ItemParticipatesIn3DContext(this, item) && !item->GetClip().HasClip()) {
        // The frame of this item participates the same 3D context.
        WrapSeparatorTransform(aBuilder, this, dirtyRect,
                               &nonparticipants, &participants, index++);
        participants.AppendToTop(item);
      } else {
        // The frame of the item doesn't participate the current
        // context, or has no transform.
        //
        // For items participating but not transformed, they are add
        // to nonparticipants to get a separator layer for handling
        // clips, if there is, on an intermediate surface.
        // \see ContainerLayer::DefaultComputeEffectiveTransforms().
        nonparticipants.AppendToTop(item);
      }
    }
    WrapSeparatorTransform(aBuilder, this, dirtyRect,
                           &nonparticipants, &participants, index++);
    resultList.AppendToTop(&participants);
  }

  if (isTransformed && !resultList.IsEmpty()) {
    if (clipCapturedBy == ContainerItemType::eTransform) {
      // Restore clip state now so nsDisplayTransform is clipped properly.
      clipState.ExitStackingContextContents(&containerItemScrollClip);
    }
    // Revert to the dirtyrect coming in from the parent, without our transform
    // taken into account.
    buildingDisplayList.SetDirtyRect(dirtyRectOutsideTransform);
    // Revert to the outer reference frame and offset because all display
    // items we create from now on are outside the transform.
    nsPoint toOuterReferenceFrame;
    const nsIFrame* outerReferenceFrame = this;
    if (this != aBuilder->RootReferenceFrame()) {
      outerReferenceFrame =
        aBuilder->FindReferenceFrameFor(GetParent(), &toOuterReferenceFrame);
    }
    buildingDisplayList.SetReferenceFrameAndCurrentOffset(outerReferenceFrame,
      GetOffsetToCrossDoc(outerReferenceFrame));

    if (!aBuilder->IsForGenerateGlyphMask() &&
        !aBuilder->IsForPaintingSelectionBG()) {
      bool isFullyVisible =
        dirtyRectOutsideSVGEffects.Contains(GetVisualOverflowRectRelativeToSelf());
      nsDisplayTransform *transformItem =
        new (aBuilder) nsDisplayTransform(aBuilder, this,
                                          &resultList, dirtyRect, 0,
                                          isFullyVisible);
      resultList.AppendNewToTop(transformItem);
    }

    if (hasPerspective) {
      if (clipCapturedBy == ContainerItemType::ePerspective) {
        clipState.ExitStackingContextContents(&containerItemScrollClip);
      }
      resultList.AppendNewToTop(
        new (aBuilder) nsDisplayPerspective(
          aBuilder, this,
          GetContainingBlock()->GetContent()->GetPrimaryFrame(), &resultList));
    }
  }

  if (clipCapturedBy == ContainerItemType::eOwnLayerForTransformWithRoundedClip) {
    clipState.ExitStackingContextContents(&containerItemScrollClip);
    resultList.AppendNewToTop(
      new (aBuilder) nsDisplayOwnLayer(aBuilder, this, &resultList, 0,
                                       mozilla::layers::FrameMetrics::NULL_SCROLL_ID,
                                       0.0f, /* aForceActive = */ false));
  }

  /* If we have sticky positioning, wrap it in a sticky position item.
   */
  if (useFixedPosition) {
    if (clipCapturedBy == ContainerItemType::eFixedPosition) {
      clipState.ExitStackingContextContents(&containerItemScrollClip);
    }
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplayFixedPosition(aBuilder, this, &resultList));
  } else if (useStickyPosition) {
    if (clipCapturedBy == ContainerItemType::eStickyPosition) {
      clipState.ExitStackingContextContents(&containerItemScrollClip);
    }
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplayStickyPosition(aBuilder, this, &resultList));
  }

  /* If there's blending, wrap up the list in a blend-mode item. Note
   * that opacity can be applied before blending as the blend color is
   * not affected by foreground opacity (only background alpha).
   */

  if (useBlendMode && !resultList.IsEmpty()) {
    DisplayListClipState::AutoSaveRestore mixBlendClipState(aBuilder);
    mixBlendClipState.Clear();
    resultList.AppendNewToTop(
        new (aBuilder) nsDisplayBlendMode(aBuilder, this, &resultList,
                                          effects->mMixBlendMode,
                                          containerItemScrollClip));
  }

  CreateOwnLayerIfNeeded(aBuilder, &resultList);

  aList->AppendToTop(&resultList);
}

static nsDisplayItem*
WrapInWrapList(nsDisplayListBuilder* aBuilder,
               nsIFrame* aFrame, nsDisplayList* aList,
               const DisplayItemScrollClip* aScrollClip)
{
  nsDisplayItem* item = aList->GetBottom();
  if (!item) {
    return nullptr;
  }

  // For perspective items we want to treat the 'frame' as being the transform
  // frame that created it. This stops the transform frame from wrapping another
  // nsDisplayWrapList around it (with mismatching reference frames), but still
  // makes the perspective frame create one (so we have an atomic entry for z-index
  // sorting).
  nsIFrame *itemFrame = item->Frame();
  if (item->GetType() == nsDisplayItem::TYPE_PERSPECTIVE) {
    itemFrame = static_cast<nsDisplayPerspective*>(item)->TransformFrame();
  }

  if (item->GetAbove() || itemFrame != aFrame) {
    return new (aBuilder) nsDisplayWrapList(aBuilder, aFrame, aList, aScrollClip);
  }
  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;

  if (aBuilder->IsForGenerateGlyphMask() ||
      aBuilder->IsForPaintingSelectionBG()) {
    if (nsGkAtoms::textFrame != aChild->GetType() && aChild->IsLeaf()) {
      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;
  bool isPlaceholder = false;
  if (childType == nsGkAtoms::placeholderFrame) {
    isPlaceholder = true;
    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;
    MOZ_ASSERT(child->GetStateBits() & NS_FRAME_OUT_OF_FLOW);
    // If the out-of-flow frame is in the top layer, the viewport frame
    // will paint it. Skip it here. Note that, only out-of-flow frames
    // with this property should be skipped, because non-HTML elements
    // may stop their children from being out-of-flow. Those frames
    // should still be handled in the normal in-flow path.
    if (placeholder->GetStateBits() & PLACEHOLDER_FOR_TOPLAYER) {
      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 = nsDisplayListBuilder::GetOutOfFlowData(child);
    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;
  }

  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.
    // There are cases where the "ignore scroll frame" on the builder is not set
    // correctly, and so we additionally want to catch cases where the child is
    // a root scrollframe and we are ignoring scrolling on the viewport.
    nsIPresShell* shell = PresContext()->PresShell();
    bool keepDescending = child == aBuilder->GetIgnoreScrollFrame() ||
        (shell->IgnoringViewportScrolling() && child == shell->GetRootScrollFrame());
    if (!keepDescending) {
      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 or a blend mode..
  const nsStyleDisplay* disp = child->StyleDisplay();
  const nsStyleEffects* effects = child->StyleEffects();
  const nsStylePosition* pos = child->StylePosition();
  bool isVisuallyAtomic = child->HasOpacity()
    || child->IsTransformed()
    // strictly speaking, 'perspective' doesn't require visual atomicity,
    // but the spec says it acts like the rest of these
    || disp->mChildPerspective.GetUnit() == eStyleUnit_Coord
    || effects->mMixBlendMode != NS_STYLE_BLEND_NORMAL
    || nsSVGIntegrationUtils::UsingEffectsForFrame(child);

  bool isPositioned = disp->IsAbsPosContainingBlock(child);
  bool isStackingContext =
    (isPositioned && (disp->IsPositionForcingStackingContext() ||
                      pos->mZIndex.GetUnit() == eStyleUnit_Integer)) ||
     (disp->mWillChangeBitField & NS_STYLE_WILL_CHANGE_STACKING_CONTEXT) ||
     disp->mIsolation != NS_STYLE_ISOLATION_AUTO ||
     isVisuallyAtomic || (aFlags & DISPLAY_CHILD_FORCE_STACKING_CONTEXT);

  if (isVisuallyAtomic || isPositioned || (!isSVG && disp->IsFloating(child)) ||
      ((effects->mClipFlags & NS_STYLE_CLIP_RECT) &&
       IsSVGContentWithCSSClip(child)) ||
       disp->mIsolation != NS_STYLE_ISOLATION_AUTO ||
       (disp->mWillChangeBitField & NS_STYLE_WILL_CHANGE_STACKING_CONTEXT) ||
      (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");

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

  if (savedOutOfFlowData) {
    aBuilder->SetBuildingInvisibleItems(false);

    clipState.SetClipForContainingBlockDescendants(
      &savedOutOfFlowData->mContainingBlockClip);
    clipState.SetScrollClipForContainingBlockDescendants(aBuilder,
      savedOutOfFlowData->mContainingBlockScrollClip);
  } else if (GetStateBits() & NS_FRAME_FORCE_DISPLAY_LIST_DESCEND_INTO &&
             isPlaceholder) {
    NS_ASSERTION(dirty.IsEmpty(), "should have empty dirty rect");
    // Every item we build from now until we descent into an out of flow that
    // does have saved out of flow data should be invisible. This state gets
    // restored when AutoBuildingDisplayList gets out of scope.
    aBuilder->SetBuildingInvisibleItems(true);

    // If we have nested out-of-flow frames and the outer one isn't visible
    // then we won't have stored clip data for it. We can just clear the clip
    // instead since we know we won't render anything, and the inner out-of-flow
    // frame will setup the correct clip for itself.
    clipState.SetClipForContainingBlockDescendants(nullptr);
    clipState.SetScrollClipForContainingBlockDescendants(aBuilder, nullptr);
  }

  // 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) {
    if (effects->mMixBlendMode != NS_STYLE_BLEND_NORMAL) {
      aBuilder->SetContainsBlendMode(true);
    }
    // True stacking context.
    // For stacking contexts, BuildDisplayListForStackingContext handles
    // clipping and MarkAbsoluteFramesForDisplayList.
    child->BuildDisplayListForStackingContext(aBuilder, dirty, &list);
    aBuilder->DisplayCaret(child, dirty, &list);
  } else {
    Maybe<nsRect> clipPropClip =
      child->GetClipPropClipRect(disp, effects, child->GetSize());
    if (clipPropClip) {
      dirty.IntersectRect(dirty, *clipPropClip);
      clipState.ClipContentDescendants(
        *clipPropClip + aBuilder->ToReferenceFrame(child));
    }

    child->MarkAbsoluteFramesForDisplayList(aBuilder, dirty);

    if (aBuilder->IsBuildingLayerEventRegions()) {
      // If this frame has a different animated geometry root than its parent,
      // make sure we accumulate event regions for its layer.
      if (buildingForChild.IsAnimatedGeometryRoot()) {
        nsDisplayLayerEventRegions* eventRegions =
          new (aBuilder) nsDisplayLayerEventRegions(aBuilder, child);
        eventRegions->AddFrame(aBuilder, child);
        aBuilder->SetLayerEventRegions(eventRegions);
        aLists.BorderBackground()->AppendNewToTop(eventRegions);
      } else {
        nsDisplayLayerEventRegions* eventRegions = aBuilder->GetLayerEventRegions();
        if (eventRegions) {
          eventRegions->AddFrame(aBuilder, child);
        }
      }
    }

    if (!pseudoStackingContext) {
      // THIS IS THE COMMON CASE.
      // Not a pseudo or real stacking context. Do the simple thing and
      // return early.

      aBuilder->AdjustWindowDraggingRegion(child);
      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;
    aBuilder->AdjustWindowDraggingRegion(child);
    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
  }

  buildingForChild.RestoreBuildingInvisibleItemsValue();
 
  // 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();

  const DisplayItemScrollClip* containerItemScrollClip =
    aBuilder->ClipState().CurrentAncestorScrollClipForStackingContextContents();

  if (isPositioned || isVisuallyAtomic ||
      (aFlags & DISPLAY_CHILD_FORCE_STACKING_CONTEXT)) {
    // Genuine stacking contexts, and positioned pseudo-stacking-contexts,
    // go in this level.
    if (!list.IsEmpty()) {
      nsDisplayItem* item = WrapInWrapList(aBuilder, child, &list, containerItemScrollClip);
      if (isSVG) {
        aLists.Content()->AppendNewToTop(item);
      } else {
        aLists.PositionedDescendants()->AppendNewToTop(item);
      }
    }
  } else if (!isSVG && disp->IsFloating(child)) {
    if (!list.IsEmpty()) {
      aLists.Floats()->AppendNewToTop(WrapInWrapList(aBuilder, child, &list, containerItemScrollClip));
    }
  } 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);
  }
}

nsresult  
nsFrame::GetContentForEvent(WidgetEvent* 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) {
    RefPtr<AsyncEventDispatcher> asyncDispatcher =
      new AsyncEventDispatcher(target, aDOMEventName, true, false);
    DebugOnly<nsresult> rv = asyncDispatcher->PostDOMEvent();
    NS_ASSERTION(NS_SUCCEEDED(rv), "AsyncEventDispatcher failed to dispatch");
  }
}

nsresult
nsFrame::HandleEvent(nsPresContext* aPresContext, 
                     WidgetGUIEvent* aEvent,
                     nsEventStatus* aEventStatus)
{

  if (aEvent->mMessage == eMouseMove) {
    // XXX If the second argument of HandleDrag() is WidgetMouseEvent,
    //     the implementation becomes simpler.
    return HandleDrag(aPresContext, aEvent, aEventStatus);
  }

  if ((aEvent->mClass == eMouseEventClass &&
       aEvent->AsMouseEvent()->button == WidgetMouseEvent::eLeftButton) ||
      aEvent->mClass == eTouchEventClass) {
    if (aEvent->mMessage == eMouseDown || aEvent->mMessage == eTouchStart) {
      HandlePress(aPresContext, aEvent, aEventStatus);
    } else if (aEvent->mMessage == eMouseUp || aEvent->mMessage == eTouchEnd) {
      HandleRelease(aPresContext, aEvent, aEventStatus);
    }
  }
  return NS_OK;
}

NS_IMETHODIMP
nsFrame::GetDataForTableSelection(const nsFrameSelection* aFrameSelection,
                                  nsIPresShell* aPresShell,
                                  WidgetMouseEvent* 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->mMessage == eMouseMove ||
      (aMouseEvent->mMessage == eMouseUp &&
       aMouseEvent->button == WidgetMouseEvent::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)
      nsTableWrapperFrame *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
  parentContent.forget(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;
}

nsresult
nsFrame::IsSelectable(bool* aSelectable, StyleUserSelect* 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'.
  //
  // The -moz-text value acts as a way to override an ancestor's all/-moz-all value.
  //
  // For instance, if the frame hierarchy is:
  //    AUTO     -> _MOZ_ALL  -> NONE -> TEXT,      the returned value is ALL
  //    AUTO     -> _MOZ_ALL  -> NONE -> _MOZ_TEXT, the returned value is TEXT.
  //    TEXT     -> NONE      -> AUTO -> _MOZ_ALL,  the returned value is TEXT
  //    _MOZ_ALL -> TEXT      -> AUTO -> AUTO,      the returned value is ALL
  //    _MOZ_ALL -> _MOZ_TEXT -> AUTO -> AUTO,      the returned value is TEXT.
  //    AUTO     -> CELL      -> TEXT -> AUTO,      the returned value is TEXT
  //
  StyleUserSelect selectStyle  = StyleUserSelect::Auto;
  nsIFrame* frame              = const_cast<nsFrame*>(this);
  bool containsEditable        = false;

  while (frame) {
    const nsStyleUIReset* userinterface = frame->StyleUIReset();
    switch (userinterface->mUserSelect) {
      case StyleUserSelect::All:
      case StyleUserSelect::MozAll:
      {
        // override the previous values
        if (selectStyle != StyleUserSelect::MozText) {
          selectStyle = userinterface->mUserSelect;
        }
        nsIContent* frameContent = frame->GetContent();
        containsEditable = frameContent &&
          frameContent->EditableDescendantCount() > 0;
        break;
      }
      default:
        // otherwise return the first value which is not 'auto'
        if (selectStyle == StyleUserSelect::Auto) {
          selectStyle = userinterface->mUserSelect;
        }
        break;
    }
    frame = nsLayoutUtils::GetParentOrPlaceholderFor(frame);
  }

  // convert internal values to standard values
  if (selectStyle == StyleUserSelect::Auto ||
      selectStyle == StyleUserSelect::MozText) {
    selectStyle = StyleUserSelect::Text;
  } else if (selectStyle == StyleUserSelect::MozAll) {
    selectStyle = StyleUserSelect::All;
  }

  // If user tries to select all of a non-editable content,
  // prevent selection if it contains editable content.
  bool allowSelection = true;
  if (selectStyle == StyleUserSelect::All) {
    allowSelection = !containsEditable;
  }

  // return stuff
  if (aSelectStyle) {
    *aSelectStyle = selectStyle;
  }

  if (mState & NS_FRAME_GENERATED_CONTENT) {
    *aSelectable = false;
  } else {
    *aSelectable = allowSelection && (selectStyle != StyleUserSelect::None);
  }

  return NS_OK;
}

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

  NS_ENSURE_ARG_POINTER(aEvent);
  if (aEvent->mClass == eTouchEventClass) {
    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;

  WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();

  if (!mouseEvent->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(mouseEvent, this))) {
          return NS_OK;
        }
      }
    }
  }

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

  // When implementing StyleUserSelect::Element, StyleUserSelect::Elements and
  // StyleUserSelect::Toggle, need to change this logic
  bool useFrameSelection = (selectStyle == StyleUserSelect::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.
  bool hasCapturedContent = false;
  if (!nsIPresShell::GetCapturingContent()) {
    nsIScrollableFrame* scrollFrame =
      nsLayoutUtils::GetNearestScrollableFrame(this,
        nsLayoutUtils::SCROLLABLE_SAME_DOC |
        nsLayoutUtils::SCROLLABLE_INCLUDE_HIDDEN);
    if (scrollFrame) {
      nsIFrame* capturingFrame = do_QueryFrame(scrollFrame);
      nsIPresShell::SetCapturingContent(capturingFrame->GetContent(),
                                        CAPTURE_IGNOREALLOWED);
      hasCapturedContent = true;
    }
  }

  // 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

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

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

  nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(mouseEvent, 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)) {
    // On touchables devices, mouse events are generated if the gesture is a tap.
    // Such events are never going to generate a drag action, so let's release
    // captured content if any.
    if (hasCapturedContent) {
      nsIPresShell::SetCapturingContent(nullptr, 0);
    }

    return fc->HandleClick(offsets.content, offsets.StartOffset(),
                           offsets.EndOffset(), false, false,
                           offsets.associate);
  }

  // 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, mouseEvent,
                                getter_AddRefs(parentContent), &contentOffset,
                                &target);
  if (NS_SUCCEEDED(rv) && parentContent)
  {
    fc->SetDragState(true);
    return fc->HandleTableSelection(parentContent, contentOffset, target,
                                    mouseEvent);
  }

  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->mSelectionType != SelectionType::eSpellCheck &&
          curDetail->mSelectionType != SelectionType::eFind &&
          curDetail->mSelectionType != SelectionType::eURLSecondary &&
          curDetail->mSelectionType != SelectionType::eURLStrikeout &&
          curDetail->mStart <= offsets.StartOffset() &&
          offsets.EndOffset() <= curDetail->mEnd)
      {
        inSelection = true;
      }

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

    if (inSelection) {
      fc->SetDragState(false);
      fc->SetDelayedCaretData(mouseEvent);
      return NS_OK;
    }
  }

  fc->SetDragState(true);

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

  if (NS_FAILED(rv))
    return rv;

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

  if (isEditor && !mouseEvent->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->SetDragState(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,
                          offsets.associate, &offset);
  if (!theFrame)
    return NS_ERROR_FAILURE;

  nsFrame* frame = static_cast<nsFrame*>(theFrame);
  return frame->PeekBackwardAndForward(aBeginAmountType, aEndAmountType, offset,
                                       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,
                             WidgetGUIEvent* 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;
  WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();
  if (!mouseEvent) {
    return NS_OK;
  }

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

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

nsresult
nsFrame::PeekBackwardAndForward(nsSelectionAmount aAmountBack,
                                nsSelectionAmount aAmountForward,
                                int32_t aStartPos,
                                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,
                           nsPoint(0, 0),
                           aJumpLines,
                           true,  //limit on scrolled views
                           false,
                           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,
                              nsPoint(0, 0),
                              aJumpLines,
                              true,  //limit on scrolled views
                              false,
                              false,
                              false);
  rv = baseFrame->PeekOffset(&startpos);
  if (NS_FAILED(rv))
    return rv;

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

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

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

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

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

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

  RefPtr<nsFrameSelection> frameselection = GetFrameSelection();
  bool mouseDown = frameselection->GetDragState();
  if (!mouseDown) {
    return NS_OK;
  }

  nsIFrame* scrollbar =
    nsLayoutUtils::GetClosestFrameOfType(this, nsGkAtoms::scrollbarFrame);
  if (!scrollbar) {
    // 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.
    // NOTE: DisplaySelection() returns SELECTION_OFF for non-selectable frames.
    if (DisplaySelection(aPresContext) == nsISelectionController::SELECTION_OFF) {
      return NS_OK;
    }
  }

  frameselection->StopAutoScrollTimer();

  // Check if we are dragging in a table cell
  nsCOMPtr<nsIContent> parentContent;
  int32_t contentOffset;
  int32_t target;
  WidgetMouseEvent* mouseEvent = aEvent->AsMouseEvent();
  nsCOMPtr<nsIPresShell> presShell = aPresContext->PresShell();
  nsresult result;
  result = GetDataForTableSelection(frameselection, presShell, mouseEvent,
                                    getter_AddRefs(parentContent),
                                    &contentOffset, &target);      

  nsWeakFrame weakThis = this;
  if (NS_SUCCEEDED(result) && parentContent) {
    frameselection->HandleTableSelection(parentContent, contentOffset, target,
                                         mouseEvent);
  } else {
    nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(mouseEvent, 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
  nsIScrollableFrame* scrollFrame =
    nsLayoutUtils::GetNearestScrollableFrame(this,
        nsLayoutUtils::SCROLLABLE_SAME_DOC |
        nsLayoutUtils::SCROLLABLE_INCLUDE_HIDDEN);

  if (scrollFrame) {
    nsIFrame* capturingFrame = scrollFrame->GetScrolledFrame();
    if (capturingFrame) {
      nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(mouseEvent,
                                                                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,
                     WidgetGUIEvent*           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->SetDragState(true);

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

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

  return NS_OK;
}

NS_IMETHODIMP nsFrame::HandleRelease(nsPresContext* aPresContext,
                                     WidgetGUIEvent* aEvent,
                                     nsEventStatus* aEventStatus)
{
  if (aEvent->mClass != eMouseEventClass) {
    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);

  RefPtr<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!

      if (frameselection->MouseDownRecorded()) {
        nsPoint pt = nsLayoutUtils::GetEventCoordinatesRelativeTo(aEvent, this);
        offsets = GetContentOffsetsFromPoint(pt, SKIP_HIDDEN);
        handleTableSelection = false;
      } else {
        GetDataForTableSelection(frameselection, PresContext()->PresShell(),
                                 aEvent->AsMouseEvent(),
                                 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.
  RefPtr<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->GetUncomposedDoc();
    if (doc) {
      nsIPresShell* capturingShell = doc->GetShell();
      if (capturingShell && capturingShell != PresContext()->GetPresShell()) {
        frameSelection = capturingShell->FrameSelection();
      }
    }
  }

  if (frameSelection) {
    frameSelection->SetDragState(false);
    frameSelection->StopAutoScrollTimer();
    nsIScrollableFrame* scrollFrame =
      nsLayoutUtils::GetNearestScrollableFrame(this,
        nsLayoutUtils::SCROLLABLE_SAME_DOC |
        nsLayoutUtils::SCROLLABLE_INCLUDE_HIDDEN);
    if (scrollFrame) {
      // Perform any additional scrolling needed to maintain CSS snap point
      // requirements when autoscrolling is over.
      scrollFrame->ScrollSnap();
    }
  }

  // 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 MOZ_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 != StyleUserSelect::None;
}

static bool SelectionDescendToKids(nsIFrame* aFrame) {
  StyleUserSelect 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 != StyleUserSelect::All  &&
         style != StyleUserSelect::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->PrincipalChildList().FirstChild();
    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 *closestFromIStart = nullptr, *closestFromIEnd = nullptr;
  nscoord closestIStart = aLine->IStart(), closestIEnd = aLine->IEnd();
  WritingMode wm = aLine->mWritingMode;
  LogicalPoint pt(wm, aPoint, aLine->mContainerSize);
  bool canSkipBr = false;
  for (int32_t n = aLine->GetChildCount(); n;
       --n, frame = frame->GetNextSibling()) {
    // Skip brFrames. Can only skip if the line contains at least
    // one selectable and non-empty frame before
    if (!SelfIsSelectable(frame, aFlags) || frame->IsEmpty() ||
        (canSkipBr && frame->GetType() == nsGkAtoms::brFrame)) {
      continue;
    }
    canSkipBr = true;
    LogicalRect frameRect = LogicalRect(wm, frame->GetRect(),
                                        aLine->mContainerSize);
    if (pt.I(wm) >= frameRect.IStart(wm)) {
      if (pt.I(wm) < frameRect.IEnd(wm)) {
        return GetSelectionClosestFrameForChild(frame, aPoint, aFlags);
      }
      if (frameRect.IEnd(wm) >= closestIStart) {
        closestFromIStart = frame;
        closestIStart = frameRect.IEnd(wm);
      }
    } else {
      if (frameRect.IStart(wm) <= closestIEnd) {
        closestFromIEnd = frame;
        closestIEnd = frameRect.IStart(wm);
      }
    }
  }
  if (!closestFromIStart && !closestFromIEnd) {
    // 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 (closestFromIStart &&
      (!closestFromIEnd ||
       (abs(pt.I(wm) - closestIStart) <= abs(pt.I(wm) - closestIEnd)))) {
    return GetSelectionClosestFrameForChild(closestFromIStart, aPoint,
                                            aFlags);
  }
  return GetSelectionClosestFrameForChild(closestFromIEnd, 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;
  // Convert aPoint into a LogicalPoint in the writing-mode of this block
  WritingMode wm = curLine->mWritingMode;
  LogicalPoint pt(wm, aPoint, curLine->mContainerSize);
  while (curLine != end) {
    // Check to see if our point lies within the line's block-direction bounds
    nscoord BCoord = pt.B(wm) - curLine->BStart();
    nscoord BSize = curLine->BSize();
    if (BCoord >= 0 && BCoord < BSize) {
      closestLine = curLine;
      break; // We found the line; stop looking
    }
    if (BCoord < 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 (pt.B(wm) - prevLine->BEnd() < nextLine->BStart() - pt.B(wm))
        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->PrincipalChildList().FirstChild();

  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.associate = CARET_ASSOCIATE_AFTER;
    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() != StyleDisplay::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.associate =
      offsets.offset == range.start ? CARET_ASSOCIATE_AFTER : CARET_ASSOCIATE_BEFORE;
  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.
    StyleUserSelect userSelect = frame->StyleUIReset()->mUserSelect;
    if (userSelect == StyleUserSelect::MozText) {
      // If we see a -moz-text element, we shouldn't look further up the parent
      // chain!
      break;
    }
    if (userSelect == StyleUserSelect::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 ==
        StyleUserSelect::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.associate = CARET_ASSOCIATE_AFTER;
    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.associate = offsets.offset == range.start ?
        CARET_ASSOCIATE_AFTER : CARET_ASSOCIATE_BEFORE;
    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);
}

void
nsIFrame::AssociateImage(const nsStyleImage& aImage, nsPresContext* aPresContext)
{
  if (aImage.GetType() != eStyleImageType_Image) {
    return;
  }

  imgIRequest *req = aImage.GetImageData();
  mozilla::css::ImageLoader* loader =
    aPresContext->Document()->StyleImageLoader();

  // If this fails there's not much we can do ...
  loader->AssociateRequestToFrame(req, this);
}

nsresult
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;
  }
  if (NS_STYLE_CURSOR_TEXT == aCursor.mCursor &&
      GetWritingMode().IsVertical()) {
    // Per CSS UI spec, UA may treat value 'text' as
    // 'vertical-text' for vertical text.
    aCursor.mCursor = NS_STYLE_CURSOR_VERTICAL_TEXT;
  }

  return NS_OK;
}

// Resize and incremental reflow

/* virtual */ void
nsFrame::MarkIntrinsicISizesDirty()
{
  // This version is meant only for what used to be box-to-block adaptors.
  // It should not be called by other derived classes.
  if (::IsXULBoxWrapped(this)) {
    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::GetMinISize(nsRenderingContext *aRenderingContext)
{
  nscoord result = 0;
  DISPLAY_MIN_WIDTH(this, result);
  return result;
}

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

/* virtual */ void
nsFrame::AddInlineMinISize(nsRenderingContext* aRenderingContext,
                           nsIFrame::InlineMinISizeData* aData)
{
  nscoord isize = nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
                    this, nsLayoutUtils::MIN_ISIZE);
  aData->DefaultAddInlineMinISize(this, isize);
}

/* virtual */ void
nsFrame::AddInlinePrefISize(nsRenderingContext* aRenderingContext,
                            nsIFrame::InlinePrefISizeData* aData)
{
  nscoord isize = nsLayoutUtils::IntrinsicForContainer(aRenderingContext,
                    this, nsLayoutUtils::PREF_ISIZE);
  aData->DefaultAddInlinePrefISize(isize);
}

void
nsIFrame::InlineMinISizeData::DefaultAddInlineMinISize(nsIFrame* aFrame,
                                                       nscoord   aISize,
                                                       bool      aAllowBreak)
{
  auto parent = aFrame->GetParent();
  MOZ_ASSERT(parent, "Must have a parent if we get here!");
  const bool mayBreak = aAllowBreak &&
    !aFrame->CanContinueTextRun() &&
    !parent->StyleContext()->ShouldSuppressLineBreak() &&
    parent->StyleText()->WhiteSpaceCanWrap(parent);
  if (mayBreak) {
    OptionallyBreak();
  }
  mTrailingWhitespace = 0;
  mSkipWhitespace = false;
  mCurrentLine += aISize;
  mAtStartOfLine = false;
  if (mayBreak) {
    OptionallyBreak();
  }
}

void
nsIFrame::InlinePrefISizeData::DefaultAddInlinePrefISize(nscoord aISize)
{
  mCurrentLine = NSCoordSaturatingAdd(mCurrentLine, aISize);
  mTrailingWhitespace = 0;
  mSkipWhitespace = false;
  mLineIsEmpty = false;
}

void
nsIFrame::InlineMinISizeData::ForceBreak()
{
  mCurrentLine -= mTrailingWhitespace;
  mPrevLines = std::max(mPrevLines, mCurrentLine);
  mCurrentLine = mTrailingWhitespace = 0;

  for (uint32_t i = 0, i_end = mFloats.Length(); i != i_end; ++i) {
    nscoord float_min = mFloats[i].Width();
    if (float_min > mPrevLines)
      mPrevLines = float_min;
  }
  mFloats.Clear();
  mSkipWhitespace = true;
}

void
nsIFrame::InlineMinISizeData::OptionallyBreak(nscoord aHyphenWidth)
{
  // 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 (mCurrentLine + aHyphenWidth < 0 || mAtStartOfLine)
    return;
  mCurrentLine += aHyphenWidth;
  ForceBreak();
}

void
nsIFrame::InlinePrefISizeData::ForceBreak()
{
  if (mFloats.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 = mFloats.Length(); i != i_end; ++i) {
      const FloatInfo& floatInfo = mFloats[i];
      const nsStyleDisplay* floatDisp = floatInfo.Frame()->StyleDisplay();
      StyleClear breakType = floatDisp->PhysicalBreakType(mLineContainerWM);
      if (breakType == StyleClear::Left ||
          breakType == StyleClear::Right ||
          breakType == StyleClear::Both) {
        nscoord floats_cur = NSCoordSaturatingAdd(floats_cur_left,
                                                  floats_cur_right);
        if (floats_cur > floats_done) {
          floats_done = floats_cur;
        }
        if (breakType != StyleClear::Right) {
          floats_cur_left = 0;
        }
        if (breakType != StyleClear::Left) {
          floats_cur_right = 0;
        }
      }

      StyleFloat floatStyle = floatDisp->PhysicalFloats(mLineContainerWM);
      nscoord& floats_cur =
        floatStyle == StyleFloat::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;

    mCurrentLine = NSCoordSaturatingAdd(mCurrentLine, floats_done);

    mFloats.Clear();
  }

  mCurrentLine =
    NSCoordSaturatingSubtract(mCurrentLine, mTrailingWhitespace, nscoord_MAX);
  mPrevLines = std::max(mPrevLines, mCurrentLine);
  mCurrentLine = mTrailingWhitespace = 0;
  mSkipWhitespace = true;
  mLineIsEmpty = true;
}

static void
AddCoord(const nsStyleCoord& aStyle,
         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;
    }
  }
}

static nsIFrame::IntrinsicISizeOffsetData
IntrinsicSizeOffsets(nsIFrame* aFrame, bool aForISize)
{
  nsIFrame::IntrinsicISizeOffsetData result;
  WritingMode wm = aFrame->GetWritingMode();
  const nsStyleMargin* styleMargin = aFrame->StyleMargin();
  bool verticalAxis = aForISize == wm.IsVertical();
  AddCoord(verticalAxis ? styleMargin->mMargin.GetTop()
                        : styleMargin->mMargin.GetLeft(),
           aFrame, &result.hMargin, &result.hPctMargin,
           false);
  AddCoord(verticalAxis ? styleMargin->mMargin.GetBottom()
                        : styleMargin->mMargin.GetRight(),
           aFrame, &result.hMargin, &result.hPctMargin,
           false);

  const nsStylePadding* stylePadding = aFrame->StylePadding();
  AddCoord(verticalAxis ? stylePadding->mPadding.GetTop()
                        : stylePadding->mPadding.GetLeft(),
           aFrame, &result.hPadding, &result.hPctPadding,
           true);
  AddCoord(verticalAxis ? stylePadding->mPadding.GetBottom()
                        : stylePadding->mPadding.GetRight(),
           aFrame, &result.hPadding, &result.hPctPadding,
           true);

  const nsStyleBorder* styleBorder = aFrame->StyleBorder();
  if (verticalAxis) {
    result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_TOP);
    result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_BOTTOM);
  } else {
    result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_LEFT);
    result.hBorder += styleBorder->GetComputedBorderWidth(NS_SIDE_RIGHT);
  }

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

    nsIntMargin border;
    presContext->GetTheme()->GetWidgetBorder(presContext->DeviceContext(),
                                             aFrame, disp->mAppearance,
                                             &border);
    result.hBorder =
      presContext->DevPixelsToAppUnits(verticalAxis ? border.TopBottom()
                                                    : border.LeftRight());

    nsIntMargin padding;
    if (presContext->GetTheme()->GetWidgetPadding(presContext->DeviceContext(),
                                                  aFrame, disp->mAppearance,
                                                  &padding)) {
      result.hPadding =
        presContext->DevPixelsToAppUnits(verticalAxis ? padding.TopBottom()
                                                      : padding.LeftRight());
      result.hPctPadding = 0;
    }
  }
  return result;
}

/* virtual */ nsIFrame::IntrinsicISizeOffsetData
nsFrame::IntrinsicISizeOffsets()
{
  return IntrinsicSizeOffsets(this, true);
}

nsIFrame::IntrinsicISizeOffsetData
nsIFrame::IntrinsicBSizeOffsets()
{
  return IntrinsicSizeOffsets(this, false);
}

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

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

/* virtual */
LogicalSize
nsFrame::ComputeSize(nsRenderingContext *aRenderingContext,
                     WritingMode aWM,
                     const LogicalSize& aCBSize,
                     nscoord aAvailableISize,
                     const LogicalSize& aMargin,
                     const LogicalSize& aBorder,
                     const LogicalSize& aPadding,
                     ComputeSizeFlags aFlags)
{
  MOZ_ASSERT(GetIntrinsicRatio() == nsSize(0,0),
             "Please override this method and call "
             "nsLayoutUtils::ComputeSizeWithIntrinsicDimensions instead.");
  LogicalSize result = ComputeAutoSize(aRenderingContext, aWM,
                                       aCBSize, aAvailableISize,
                                       aMargin, aBorder, aPadding,
                                       aFlags & ComputeSizeFlags::eShrinkWrap);
  const nsStylePosition *stylePos = StylePosition();

  LogicalSize boxSizingAdjust(aWM);
  if (stylePos->mBoxSizing == StyleBoxSizing::Border) {
    boxSizingAdjust = aBorder + aPadding;
  }
  nscoord boxSizingToMarginEdgeISize =
    aMargin.ISize(aWM) + aBorder.ISize(aWM) + aPadding.ISize(aWM) -
    boxSizingAdjust.ISize(aWM);

  const nsStyleCoord* inlineStyleCoord = &stylePos->ISize(aWM);
  const nsStyleCoord* blockStyleCoord = &stylePos->BSize(aWM);

  nsIAtom* parentFrameType = GetParent() ? GetParent()->GetType() : nullptr;
  bool isGridItem = (parentFrameType == nsGkAtoms::gridContainerFrame &&
                     !(GetStateBits() & NS_FRAME_OUT_OF_FLOW));
  bool isFlexItem = (parentFrameType == nsGkAtoms::flexContainerFrame &&
                     !(GetStateBits() & NS_FRAME_OUT_OF_FLOW));
  bool isInlineFlexItem = false;
  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 = GetParent()->StylePosition()->mFlexDirection;
    isInlineFlexItem =
      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW ||
      flexDirection == NS_STYLE_FLEX_DIRECTION_ROW_REVERSE;

    // NOTE: The logic here should match the similar chunk for determining
    // inlineStyleCoord and blockStyleCoord in
    // nsLayoutUtils::ComputeSizeWithIntrinsicDimensions().
    const nsStyleCoord* flexBasis = &(stylePos->mFlexBasis);
    if (flexBasis->GetUnit() != eStyleUnit_Auto) {
      if (isInlineFlexItem) {
        inlineStyleCoord = 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) {
          blockStyleCoord = flexBasis;
        }
      }
    }
  }

  // Compute inline-axis size

  if (inlineStyleCoord->GetUnit() != eStyleUnit_Auto) {
    result.ISize(aWM) =
      nsLayoutUtils::ComputeISizeValue(aRenderingContext, this,
        aCBSize.ISize(aWM), boxSizingAdjust.ISize(aWM), boxSizingToMarginEdgeISize,
        *inlineStyleCoord);
  }

  // Flex items ignore their min & max sizing properties in their
  // flex container's main-axis.  (Those properties get applied later in
  // the flexbox algorithm.)
  const nsStyleCoord& maxISizeCoord = stylePos->MaxISize(aWM);
  nscoord maxISize = NS_UNCONSTRAINEDSIZE;
  if (maxISizeCoord.GetUnit() != eStyleUnit_None &&
      !(isFlexItem && isInlineFlexItem)) {
    maxISize =
      nsLayoutUtils::ComputeISizeValue(aRenderingContext, this,
        aCBSize.ISize(aWM), boxSizingAdjust.ISize(aWM), boxSizingToMarginEdgeISize,
        maxISizeCoord);
    result.ISize(aWM) = std::min(maxISize, result.ISize(aWM));
  }

  const nsStyleCoord& minISizeCoord = stylePos->MinISize(aWM);
  nscoord minISize;
  if (minISizeCoord.GetUnit() != eStyleUnit_Auto &&
      !(isFlexItem && isInlineFlexItem)) {
    minISize =
      nsLayoutUtils::ComputeISizeValue(aRenderingContext, this,
        aCBSize.ISize(aWM), boxSizingAdjust.ISize(aWM), boxSizingToMarginEdgeISize,
        minISizeCoord);
  } else if (MOZ_UNLIKELY(isGridItem)) {
    // This implements "Implied Minimum Size of Grid Items".
    // https://drafts.csswg.org/css-grid/#min-size-auto
    minISize = std::min(maxISize, GetMinISize(aRenderingContext));
    if (inlineStyleCoord->IsCoordPercentCalcUnit()) {
      minISize = std::min(minISize, result.ISize(aWM));
    }
  } else {
    // Treat "min-width: auto" as 0.
    // NOTE: Technically, "auto" is supposed to behave like "min-content" on
    // flex items. However, we don't need to worry about that here, because
    // flex items' min-sizes are intentionally ignored until the flex
    // container explicitly considers them during space distribution.
    minISize = 0;
  }
  result.ISize(aWM) = std::max(minISize, result.ISize(aWM));

  // Compute block-axis size
  // (but not if we have auto bsize or if we recieved the "eUseAutoBSize"
  // flag -- then, we'll just stick with the bsize that we already calculated
  // in the initial ComputeAutoSize() call.)
  if (!(aFlags & nsIFrame::eUseAutoBSize)) {
    if (!nsLayoutUtils::IsAutoBSize(*blockStyleCoord, aCBSize.BSize(aWM))) {
      result.BSize(aWM) =
        nsLayoutUtils::ComputeBSizeValue(aCBSize.BSize(aWM),
                                         boxSizingAdjust.BSize(aWM),
                                         *blockStyleCoord);
    } else if (MOZ_UNLIKELY(isGridItem) &&
               blockStyleCoord->GetUnit() == eStyleUnit_Auto &&
               !IS_TRUE_OVERFLOW_CONTAINER(this)) {
      // 'auto' block-size for grid-level box - apply 'stretch' as needed:
      auto cbSize = aCBSize.BSize(aWM);
      if (cbSize != NS_AUTOHEIGHT &&
          !StyleMargin()->HasBlockAxisAuto(aWM)) {
        auto blockAxisAlignment =
          !aWM.IsOrthogonalTo(GetParent()->GetWritingMode()) ?
            StylePosition()->ComputedAlignSelf(StyleContext()->GetParent()) :
            StylePosition()->ComputedJustifySelf(StyleContext()->GetParent());
        if (blockAxisAlignment == NS_STYLE_ALIGN_NORMAL ||
            blockAxisAlignment == NS_STYLE_ALIGN_STRETCH) {
          result.BSize(aWM) = std::max(nscoord(0), cbSize -
                                                   aPadding.BSize(aWM) -
                                                   aBorder.BSize(aWM) -
                                                   aMargin.BSize(aWM));
        }
      }
    }
  }

  const nsStyleCoord& maxBSizeCoord = stylePos->MaxBSize(aWM);

  if (result.BSize(aWM) != NS_UNCONSTRAINEDSIZE) {
    if (!nsLayoutUtils::IsAutoBSize(maxBSizeCoord, aCBSize.BSize(aWM)) &&
        !(isFlexItem && !isInlineFlexItem)) {
      nscoord maxBSize =
        nsLayoutUtils::ComputeBSizeValue(aCBSize.BSize(aWM),
                                         boxSizingAdjust.BSize(aWM),
                                         maxBSizeCoord);
      result.BSize(aWM) = std::min(maxBSize, result.BSize(aWM));
    }

    const nsStyleCoord& minBSizeCoord = stylePos->MinBSize(aWM);

    if (!nsLayoutUtils::IsAutoBSize(minBSizeCoord, aCBSize.BSize(aWM)) &&
        !(isFlexItem && !isInlineFlexItem)) {
      nscoord minBSize =
        nsLayoutUtils::ComputeBSizeValue(aCBSize.BSize(aWM),
                                         boxSizingAdjust.BSize(aWM),
                                         minBSizeCoord);
      result.BSize(aWM) = std::max(minBSize, result.BSize(aWM));
    }
  }

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

    // Convert themed widget's physical dimensions to logical coords
    LogicalSize size(aWM,
                     nsSize(presContext->DevPixelsToAppUnits(widget.width),
                            presContext->DevPixelsToAppUnits(widget.height)));

    // GMWS() returns border-box; we need content-box
    size.ISize(aWM) -= aBorder.ISize(aWM) + aPadding.ISize(aWM);
    size.BSize(aWM) -= aBorder.BSize(aWM) + aPadding.BSize(aWM);

    if (size.BSize(aWM) > result.BSize(aWM) || !canOverride) {
      result.BSize(aWM) = size.BSize(aWM);
    }
    if (size.ISize(aWM) > result.ISize(aWM) || !canOverride) {
      result.ISize(aWM) = size.ISize(aWM);
    }
  }

  result.ISize(aWM) = std::max(0, result.ISize(aWM));
  result.BSize(aWM) = std::max(0, result.BSize(aWM));

  return result;
}

nsRect
nsIFrame::ComputeTightBounds(DrawTarget* aDrawTarget) const
{
  return GetVisualOverflowRect();
}

nsRect
nsFrame::ComputeSimpleTightBounds(DrawTarget* aDrawTarget) 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(aDrawTarget) + child->GetPosition());
    }
  }
  return r;
}

/* virtual */ nsresult
nsIFrame::GetPrefWidthTightBounds(nsRenderingContext* aContext,
                                  nscoord* aX,
                                  nscoord* aXMost)
{
  return NS_ERROR_NOT_IMPLEMENTED;
}

/* virtual */
LogicalSize
nsFrame::ComputeAutoSize(nsRenderingContext *aRenderingContext,
                         WritingMode aWM,
                         const mozilla::LogicalSize& aCBSize,
                         nscoord aAvailableISize,
                         const mozilla::LogicalSize& aMargin,
                         const mozilla::LogicalSize& aBorder,
                         const mozilla::LogicalSize& aPadding,
                         bool aShrinkWrap)
{
  // Use basic shrink-wrapping as a default implementation.
  LogicalSize result(aWM, 0xdeadbeef, NS_UNCONSTRAINEDSIZE);

  // don't bother setting it if the result won't be used
  if (StylePosition()->ISize(aWM).GetUnit() == eStyleUnit_Auto) {
    nscoord availBased = aAvailableISize - aMargin.ISize(aWM) -
                         aBorder.ISize(aWM) - aPadding.ISize(aWM);
    result.ISize(aWM) = 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 = GetMinISize(aRenderingContext);
  if (minWidth > aWidthInCB) {
    result = minWidth;
  } else {
    nscoord prefWidth = GetPrefISize(aRenderingContext);
    if (prefWidth > aWidthInCB) {
      result = aWidthInCB;
    } else {
      result = prefWidth;
    }
  }
  return result;
}

void
nsFrame::DidReflow(nsPresContext*           aPresContext,
                   const ReflowInput*  aReflowInput,
                   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 bsize observer if there is a percent bsize.
  // The observer may be able to initiate another reflow with a computed
  // bsize. This happens in the case where a table cell has no computed
  // bsize but can fabricate one when the cell bsize is known.
  if (aReflowInput && aReflowInput->mPercentBSizeObserver &&
      !GetPrevInFlow()) {
    const nsStyleCoord &bsize =
      aReflowInput->mStylePosition->BSize(aReflowInput->GetWritingMode());
    if (bsize.HasPercent()) {
      aReflowInput->mPercentBSizeObserver->NotifyPercentBSize(*aReflowInput);
    }
  }

  aPresContext->ReflowedFrame();
}

void
nsFrame::FinishReflowWithAbsoluteFrames(nsPresContext*           aPresContext,
                                        ReflowOutput&     aDesiredSize,
                                        const ReflowInput& aReflowInput,
                                        nsReflowStatus&          aStatus,
                                        bool                     aConstrainBSize)
{
  ReflowAbsoluteFrames(aPresContext, aDesiredSize, aReflowInput, aStatus, aConstrainBSize);

  FinishAndStoreOverflow(&aDesiredSize);
}

void
nsFrame::ReflowAbsoluteFrames(nsPresContext*           aPresContext,
                              ReflowOutput&     aDesiredSize,
                              const ReflowInput& aReflowInput,
                              nsReflowStatus&          aStatus,
                              bool                     aConstrainBSize)
{
  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 usedBorder = GetUsedBorder();
    nscoord containingBlockWidth =
      std::max(0, aDesiredSize.Width() - usedBorder.LeftRight());
    nscoord containingBlockHeight =
      std::max(0, aDesiredSize.Height() - usedBorder.TopBottom());
    nsContainerFrame* container = do_QueryFrame(this);
    NS_ASSERTION(container, "Abs-pos children only supported on container frames for now");

    nsRect containingBlock(0, 0, containingBlockWidth, containingBlockHeight);
    AbsPosReflowFlags flags =
      AbsPosReflowFlags::eCBWidthAndHeightChanged; // XXX could be optimized
    if (aConstrainBSize) {
      flags |= AbsPosReflowFlags::eConstrainHeight;
    }
    absoluteContainer->Reflow(container, aPresContext, aReflowInput, aStatus,
                              containingBlock, flags,
                              &aDesiredSize.mOverflowAreas);
  }
}

void
nsFrame::PushDirtyBitToAbsoluteFrames()
{
  if (!(GetStateBits() & NS_FRAME_IS_DIRTY)) {
    return;  // No dirty bit to push.
  }
  if (!HasAbsolutelyPositionedChildren()) {
    return;  // No absolute children to push to.
  }
  GetAbsoluteContainingBlock()->MarkAllFramesDirty();
}

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

void
nsFrame::Reflow(nsPresContext*          aPresContext,
                ReflowOutput&     aDesiredSize,
                const ReflowInput& aReflowInput,
                nsReflowStatus&          aStatus)
{
  MarkInReflow();
  DO_GLOBAL_REFLOW_COUNT("nsFrame");
  aDesiredSize.ClearSize();
  aStatus = NS_FRAME_COMPLETE;
  NS_FRAME_SET_TRUNCATION(aStatus, aReflowInput, aDesiredSize);
}

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

nsresult
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;
}

void
nsFrame::SetPrevContinuation(nsIFrame* aPrevContinuation)
{
  MOZ_ASSERT(false, "not splittable");
}

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

void
nsFrame::SetNextContinuation(nsIFrame*)
{
  MOZ_ASSERT(false, "not splittable");
}

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

void
nsFrame::SetPrevInFlow(nsIFrame* aPrevInFlow)
{
  MOZ_ASSERT(false, "not splittable");
}

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

void
nsFrame::SetNextInFlow(nsIFrame*)
{
  MOZ_ASSERT(false, "not splittable");
}

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_WITHOUT_DTOR(ViewProperty, nsView)

// 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
  nsView* value = Properties().Get(ViewProperty());
  NS_ASSERTION(value, "frame state bit was set but frame has no view");
  return value;
}

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

#ifdef DEBUG
    nsIAtom* frameType = GetType();
    NS_ASSERTION(frameType == nsGkAtoms::scrollFrame ||
                 frameType == nsGkAtoms::subDocumentFrame ||
                 frameType == nsGkAtoms::listControlFrame ||
                 frameType == nsGkAtoms::objectFrame ||
                 frameType == nsGkAtoms::viewportFrame ||
                 frameType == nsGkAtoms::menuPopupFrame,
                 "Only specific frame types can have an nsView");
#endif

    // 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;
}

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

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.ScaleToOtherAppUnits(currAPD, aAPD);
        docOffset.x = docOffset.y = 0;
      }
      currAPD = newAPD;
      docOffset += newOffset;
    }
  }
  if (f == aOther) {
    offset += docOffset.ScaleToOtherAppUnits(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;
}

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

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) {
      LayoutDeviceIntPoint 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
void
nsIFrame::GetOffsetFromView(nsPoint& aOffset, nsView** aView) const
{
  NS_PRECONDITION(nullptr != aView, "null OUT parameter pointer");
  nsIFrame* frame = const_cast<nsIFrame*>(this);

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

  if (frame) {
    *aView = frame->GetView();
  }
}

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;
}

Matrix4x4
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();

    Matrix4x4 result = nsDisplayTransform::GetResultingTransformMatrix(this,
                         nsPoint(0,0), scaleFactor,
                         nsDisplayTransform::INCLUDE_PERSPECTIVE|nsDisplayTransform::OFFSET_BY_ORIGIN,
                         nullptr);
    *aOutAncestor = nsLayoutUtils::GetCrossDocParentFrame(this);
    nsPoint delta = GetOffsetToCrossDoc(*aOutAncestor);
    /* Combine the raw transform with a translation to our parent. */
    result.PostTranslate(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) {
        LayoutDeviceIntRect screenBounds = widget->GetClientBounds();
        LayoutDeviceIntRect toplevelScreenBounds = toplevel->GetClientBounds();
        LayoutDeviceIntPoint translation =
          screenBounds.TopLeft() - toplevelScreenBounds.TopLeft();

        Matrix4x4 transformToTop;
        transformToTop._41 = translation.x;
        transformToTop._42 = translation.y;

        *aOutAncestor = docRootFrame;
        Matrix4x4 docRootTransformToTop =
          nsLayoutUtils::GetTransformToAncestor(docRootFrame, nullptr);
        if (docRootTransformToTop.IsSingular()) {
          NS_WARNING("Containing document is invisible, we can't compute a valid transform");
        } else {
          docRootTransformToTop.Invert();
          return transformToTop * docRootTransformToTop;
        }
      }
    }
  }

  *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 Matrix4x4();

  /* 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 Matrix4x4::Translation(NSAppUnitsToFloatPixels(delta.x, scaleFactor),
                                NSAppUnitsToFloatPixels(delta.y, scaleFactor),
                                0.0f);
}

static void InvalidateRenderingObservers(nsIFrame* aFrame)
{
  nsSVGEffects::InvalidateDirectRenderingObservers(aFrame);
  nsIFrame* displayRoot = nsLayoutUtils::GetDisplayRootFrame(aFrame);
  nsIFrame* parent = aFrame;
  while (parent != displayRoot &&
         (parent = nsLayoutUtils::GetCrossDocParentFrame(parent)) &&
         !parent->HasAnyStateBits(NS_FRAME_DESCENDANT_NEEDS_PAINT)) {
    nsSVGEffects::InvalidateDirectRenderingObservers(parent);
  }
}

void
SchedulePaintInternal(nsIFrame* aFrame, nsIFrame::PaintType aType = nsIFrame::PAINT_DEFAULT)
{
  nsIFrame* displayRoot = nsLayoutUtils::GetDisplayRootFrame(aFrame);
  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()->IsResourceDoc())) {
    return;
  }
  if (!pres->GetContainerWeak()) {
    NS_WARNING("Shouldn't call SchedulePaint in a detached pres context");
    return;
  }

  pres->PresShell()->ScheduleViewManagerFlush(aType == nsIFrame::PAINT_DELAYED_COMPRESS ?
                                              nsIPresShell::PAINT_DELAYED_COMPRESS :
                                              nsIPresShell::PAINT_DEFAULT);

  if (aType == nsIFrame::PAINT_DELAYED_COMPRESS) {
    return;
  }

  if (aType == nsIFrame::PAINT_DEFAULT) {
    displayRoot->AddStateBits(NS_FRAME_UPDATE_LAYER_TREE);
  }
  nsIPresShell* shell = aFrame->PresContext()->PresShell();
  if (shell) {
    shell->AddInvalidateHiddenPresShellObserver(pres->RefreshDriver());
  }
}

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->HasAnyStateBits(NS_FRAME_IS_NONDISPLAY)) {
        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) {
    SchedulePaintInternal(aFrame);
  }
  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);
  
  AutoTArray<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)) {
    AutoTArray<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 = 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;

static bool
DoesLayerHaveOutOfDateFrameMetrics(Layer* aLayer)
{
  for (uint32_t i = 0; i < aLayer->GetScrollMetadataCount(); i++) {
    const FrameMetrics& metrics = aLayer->GetFrameMetrics(i);
    if (!metrics.IsScrollable()) {
      continue;
    }
    nsIScrollableFrame* scrollableFrame =
      nsLayoutUtils::FindScrollableFrameFor(metrics.GetScrollId());
    if (!scrollableFrame) {
      // This shouldn't happen, so let's do the safe thing and trigger a full
      // paint if it does.
      return true;
    }
    nsPoint scrollPosition = scrollableFrame->GetScrollPosition();
    if (metrics.GetScrollOffset() != CSSPoint::FromAppUnits(scrollPosition)) {
      return true;
    }
  }
  return false;
}

static bool
DoesLayerOrAncestorsHaveOutOfDateFrameMetrics(Layer* aLayer)
{
  for (Layer* layer = aLayer; layer; layer = layer->GetParent()) {
    if (DoesLayerHaveOutOfDateFrameMetrics(layer)) {
      return true;
    }
  }
  return false;
}

bool
nsIFrame::TryUpdateTransformOnly(Layer** aLayerResult)
{
  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;
  }

  if (DoesLayerOrAncestorsHaveOutOfDateFrameMetrics(layer)) {
    // At least one scroll frame that can affect the position of this layer
    // has changed its scroll offset since the last paint. Schedule a full
    // paint to make sure that this layer's transform and all the frame
    // metrics that affect it are in sync.
    return false;
  }

  gfx::Matrix4x4 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;
  }
  gfx::Matrix transform;
  gfx::Matrix 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 = 0.0001f;
  if (!transform3d.Is2D(&transform) ||
      !layer->GetBaseTransform().Is2D(&previousTransform) ||
      !gfx::FuzzyEqual(transform._11, previousTransform._11, kError) ||
      !gfx::FuzzyEqual(transform._22, previousTransform._22, kError) ||
      !gfx::FuzzyEqual(transform._21, previousTransform._21, kError) ||
      !gfx::FuzzyEqual(transform._12, previousTransform._12, kError)) {
    return false;
  }
  layer->SetBaseTransformForNextTransaction(transform3d);
  *aLayerResult = layer;
  return true;
}

bool 
nsIFrame::IsInvalid(nsRect& aRect)
{
  if (!HasAnyStateBits(NS_FRAME_NEEDS_PAINT)) {
    return false;
  }
  
  if (HasAnyStateBits(NS_FRAME_HAS_INVALID_RECT)) {
    nsRect* rect = 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(PaintType aType)
{
  InvalidateRenderingObservers(this);
  SchedulePaintInternal(this, aType);
}

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

  Layer* layer = FrameLayerBuilder::GetDedicatedLayer(this, aDisplayItemKey);

  InvalidateRenderingObservers(this);

  // If the layer is being updated asynchronously, and it's being forwarded
  // to a compositor, then we don't need to invalidate.
  if ((aFlags & UPDATE_IS_ASYNC) && layer &&
      layer->Manager()->GetBackendType() == LayersBackend::LAYERS_CLIENT) {
    return layer;
  }

  if (!layer) {
    if (aFrameDamageRect && aFrameDamageRect->IsEmpty()) {
      return nullptr;
    }

    // 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.
    //
    // In the bug 930056, dialer app startup but not shown on the
    // screen because sometimes we don't have any retainned data
    // for remote type displayitem and thus Repaint event is not
    // triggered. So, always invalidate here as well.
    uint32_t displayItemKey = aDisplayItemKey;
    if (aDisplayItemKey == nsDisplayItem::TYPE_PLUGIN ||
        aDisplayItemKey == nsDisplayItem::TYPE_REMOTE) {
      displayItemKey = 0;
    }

    if (aFrameDamageRect) {
      InvalidateFrameWithRect(*aFrameDamageRect, displayItemKey);
    } else {
      InvalidateFrame(displayItemKey);
    }

    return nullptr;
  }

  if (aDamageRect && aDamageRect->IsEmpty()) {
    return layer;
  }

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

  SchedulePaintInternal(this, PAINT_COMPOSITE_ONLY);
  return layer;
}

static nsRect
ComputeEffectsRect(nsIFrame* aFrame, const nsRect& aOverflowRect,
                   const nsSize& aNewSize)
{
  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->StyleEffects()->HasFilters()) {
      aFrame->Properties().
        Set(nsIFrame::PreEffectsBBoxProperty(), new nsRect(r));
      r = nsSVGUtils::GetPostFilterVisualOverflowRect(aFrame, aOverflowRect);
    }
    return r;
  }

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

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

  return r;
}

void
nsIFrame::MovePositionBy(const nsPoint& aTranslation)
{
  nsPoint position = GetNormalPosition() + aTranslation;

  const nsMargin* computedOffsets = nullptr;
  if (IsRelativelyPositioned()) {
    computedOffsets = Properties().Get(nsIFrame::ComputedOffsetProperty());
  }
  ReflowInput::ApplyRelativePositioning(this, computedOffsets ?
                                              *computedOffsets : nsMargin(),
                                              &position);
  SetPosition(position);
}

nsRect
nsIFrame::GetNormalRect() const
{
  // It might be faster to first check
  // StyleDisplay()->IsRelativelyPositionedStyle().
  nsPoint* normalPosition = Properties().Get(NormalPositionProperty());
  if (normalPosition) {
    return nsRect(*normalPosition, GetSize());
  }
  return GetRect();
}

nsPoint
nsIFrame::GetNormalPosition() const
{
  // It might be faster to first check
  // StyleDisplay()->IsRelativelyPositionedStyle().
  nsPoint* normalPosition = Properties().Get(NormalPositionProperty());
  if (normalPosition) {
    return *normalPosition;
  }
  return GetPosition();
}

nsPoint
nsIFrame::GetPositionIgnoringScrolling()
{
  return GetParent() ? GetParent()->GetPositionOfChildIgnoringScrolling(this)
    : GetPosition();
}

nsRect
nsIFrame::GetOverflowRect(nsOverflowType aType) const
{
  MOZ_ASSERT(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()));
}

nsOverflowAreas
nsIFrame::GetOverflowAreasRelativeToSelf() const
{
  if (IsTransformed()) {
    nsOverflowAreas* preTransformOverflows =
      Properties().Get(PreTransformOverflowAreasProperty());
    if (preTransformOverflows) {
      return nsOverflowAreas(preTransformOverflows->VisualOverflow(),
                             preTransformOverflows->ScrollableOverflow());
    }
  }
  return nsOverflowAreas(GetVisualOverflowRect(),
                         GetScrollableOverflowRect());
}

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

nsRect
nsIFrame::GetVisualOverflowRectRelativeToParent() const
{
  return GetVisualOverflowRect() + mRect.TopLeft();
}

nsRect
nsIFrame::GetScrollableOverflowRectRelativeToSelf() const
{
  if (IsTransformed()) {
    nsOverflowAreas* preTransformOverflows =
      Properties().Get(PreTransformOverflowAreasProperty());
    if (preTransformOverflows)
      return preTransformOverflows->ScrollableOverflow();
  }
  return GetScrollableOverflowRect();
}

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

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

bool
nsIFrame::UpdateOverflow()
{
  MOZ_ASSERT(FrameMaintainsOverflow(),
             "Non-display SVG do not maintain visual overflow rects");

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