Add m-esr52 at 52.6.0

1 files changed, 837 insertions, 0 deletions

diff --git a/layout/generic/TextOverflow.cpp b/layout/generic/TextOverflow.cpp
new file mode 100644
index 000000000..b4d935fbf
--- /dev/null
+++ b/layout/generic/TextOverflow.cpp
@@ -0,0 +1,837 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* vim: set shiftwidth=2 tabstop=8 autoindent cindent expandtab: */
+/* 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/. */
+
+#include "TextOverflow.h"
+#include <algorithm>
+
+// Please maintain alphabetical order below
+#include "nsBlockFrame.h"
+#include "nsCaret.h"
+#include "nsContentUtils.h"
+#include "nsCSSAnonBoxes.h"
+#include "nsFontMetrics.h"
+#include "nsGfxScrollFrame.h"
+#include "nsIScrollableFrame.h"
+#include "nsLayoutUtils.h"
+#include "nsPresContext.h"
+#include "nsRect.h"
+#include "nsRenderingContext.h"
+#include "nsTextFrame.h"
+#include "nsIFrameInlines.h"
+#include "mozilla/ArrayUtils.h"
+#include "mozilla/Likely.h"
+#include "nsISelection.h"
+
+namespace mozilla {
+namespace css {
+
+class LazyReferenceRenderingDrawTargetGetterFromFrame final :
+    public gfxFontGroup::LazyReferenceDrawTargetGetter {
+public:
+  typedef mozilla::gfx::DrawTarget DrawTarget;
+
+  explicit LazyReferenceRenderingDrawTargetGetterFromFrame(nsIFrame* aFrame)
+    : mFrame(aFrame) {}
+  virtual already_AddRefed<DrawTarget> GetRefDrawTarget() override
+  {
+    RefPtr<gfxContext> ctx =
+      mFrame->PresContext()->PresShell()->CreateReferenceRenderingContext();
+    RefPtr<DrawTarget> dt = ctx->GetDrawTarget();
+    return dt.forget();
+  }
+private:
+  nsIFrame* mFrame;
+};
+
+static gfxTextRun*
+GetEllipsisTextRun(nsIFrame* aFrame)
+{
+  RefPtr<nsFontMetrics> fm =
+    nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
+  LazyReferenceRenderingDrawTargetGetterFromFrame lazyRefDrawTargetGetter(aFrame);
+  return fm->GetThebesFontGroup()->GetEllipsisTextRun(
+    aFrame->PresContext()->AppUnitsPerDevPixel(),
+    nsLayoutUtils::GetTextRunOrientFlagsForStyle(aFrame->StyleContext()),
+    lazyRefDrawTargetGetter);
+}
+
+static nsIFrame*
+GetSelfOrNearestBlock(nsIFrame* aFrame)
+{
+  return nsLayoutUtils::GetAsBlock(aFrame) ? aFrame :
+         nsLayoutUtils::FindNearestBlockAncestor(aFrame);
+}
+
+// Return true if the frame is an atomic inline-level element.
+// It's not supposed to be called for block frames since we never
+// process block descendants for text-overflow.
+static bool
+IsAtomicElement(nsIFrame* aFrame, const nsIAtom* aFrameType)
+{
+  NS_PRECONDITION(!nsLayoutUtils::GetAsBlock(aFrame) ||
+                  !aFrame->IsBlockOutside(),
+                  "unexpected block frame");
+  NS_PRECONDITION(aFrameType != nsGkAtoms::placeholderFrame,
+                  "unexpected placeholder frame");
+  return !aFrame->IsFrameOfType(nsIFrame::eLineParticipant);
+}
+
+static bool
+IsFullyClipped(nsTextFrame* aFrame, nscoord aLeft, nscoord aRight,
+               nscoord* aSnappedLeft, nscoord* aSnappedRight)
+{
+  *aSnappedLeft = aLeft;
+  *aSnappedRight = aRight;
+  if (aLeft <= 0 && aRight <= 0) {
+    return false;
+  }
+  return !aFrame->MeasureCharClippedText(aLeft, aRight,
+                                         aSnappedLeft, aSnappedRight);
+}
+
+static bool
+IsInlineAxisOverflowVisible(nsIFrame* aFrame)
+{
+  NS_PRECONDITION(nsLayoutUtils::GetAsBlock(aFrame) != nullptr,
+                  "expected a block frame");
+
+  nsIFrame* f = aFrame;
+  while (f && f->StyleContext()->GetPseudo() &&
+         f->GetType() != nsGkAtoms::scrollFrame) {
+    f = f->GetParent();
+  }
+  if (!f) {
+    return true;
+  }
+  auto overflow = aFrame->GetWritingMode().IsVertical() ?
+    f->StyleDisplay()->mOverflowY : f->StyleDisplay()->mOverflowX;
+  return overflow == NS_STYLE_OVERFLOW_VISIBLE;
+}
+
+static void
+ClipMarker(const nsRect&                          aContentArea,
+           const nsRect&                          aMarkerRect,
+           DisplayListClipState::AutoSaveRestore& aClipState)
+{
+  nscoord rightOverflow = aMarkerRect.XMost() - aContentArea.XMost();
+  nsRect markerRect = aMarkerRect;
+  if (rightOverflow > 0) {
+    // Marker overflows on the right side (content width < marker width).
+    markerRect.width -= rightOverflow;
+    aClipState.ClipContentDescendants(markerRect);
+  } else {
+    nscoord leftOverflow = aContentArea.x - aMarkerRect.x;
+    if (leftOverflow > 0) {
+      // Marker overflows on the left side
+      markerRect.width -= leftOverflow;
+      markerRect.x += leftOverflow;
+      aClipState.ClipContentDescendants(markerRect);
+    }
+  }
+}
+
+static void
+InflateIStart(WritingMode aWM, LogicalRect* aRect, nscoord aDelta)
+{
+  nscoord iend = aRect->IEnd(aWM);
+  aRect->IStart(aWM) -= aDelta;
+  aRect->ISize(aWM) = std::max(iend - aRect->IStart(aWM), 0);
+}
+
+static void
+InflateIEnd(WritingMode aWM, LogicalRect* aRect, nscoord aDelta)
+{
+  aRect->ISize(aWM) = std::max(aRect->ISize(aWM) + aDelta, 0);
+}
+
+static bool
+IsFrameDescendantOfAny(nsIFrame* aChild,
+                       const TextOverflow::FrameHashtable& aSetOfFrames,
+                       nsIFrame* aCommonAncestor)
+{
+  for (nsIFrame* f = aChild; f && f != aCommonAncestor;
+       f = nsLayoutUtils::GetCrossDocParentFrame(f)) {
+    if (aSetOfFrames.GetEntry(f)) {
+      return true;
+    }
+  }
+  return false;
+}
+
+class nsDisplayTextOverflowMarker : public nsDisplayItem
+{
+public:
+  nsDisplayTextOverflowMarker(nsDisplayListBuilder* aBuilder, nsIFrame* aFrame,
+                              const nsRect& aRect, nscoord aAscent,
+                              const nsStyleTextOverflowSide* aStyle,
+                              uint32_t aIndex)
+    : nsDisplayItem(aBuilder, aFrame), mRect(aRect),
+      mStyle(aStyle), mAscent(aAscent), mIndex(aIndex) {
+    MOZ_COUNT_CTOR(nsDisplayTextOverflowMarker);
+  }
+#ifdef NS_BUILD_REFCNT_LOGGING
+  virtual ~nsDisplayTextOverflowMarker() {
+    MOZ_COUNT_DTOR(nsDisplayTextOverflowMarker);
+  }
+#endif
+  virtual nsRect GetBounds(nsDisplayListBuilder* aBuilder,
+                           bool* aSnap) override {
+    *aSnap = false;
+    nsRect shadowRect =
+      nsLayoutUtils::GetTextShadowRectsUnion(mRect, mFrame);
+    return mRect.Union(shadowRect);
+  }
+
+  virtual nsRect GetComponentAlphaBounds(nsDisplayListBuilder* aBuilder) override
+  {
+    if (gfxPlatform::GetPlatform()->RespectsFontStyleSmoothing()) {
+      // On OS X, web authors can turn off subpixel text rendering using the
+      // CSS property -moz-osx-font-smoothing. If they do that, we don't need
+      // to use component alpha layers for the affected text.
+      if (mFrame->StyleFont()->mFont.smoothing == NS_FONT_SMOOTHING_GRAYSCALE) {
+        return nsRect();
+      }
+    }
+    bool snap;
+    return GetBounds(aBuilder, &snap);
+  }
+
+  virtual void Paint(nsDisplayListBuilder* aBuilder,
+                     nsRenderingContext* aCtx) override;
+
+  virtual uint32_t GetPerFrameKey() override { 
+    return (mIndex << nsDisplayItem::TYPE_BITS) | nsDisplayItem::GetPerFrameKey(); 
+  }
+  void PaintTextToContext(nsRenderingContext* aCtx,
+                          nsPoint aOffsetFromRect);
+  NS_DISPLAY_DECL_NAME("TextOverflow", TYPE_TEXT_OVERFLOW)
+private:
+  nsRect          mRect;   // in reference frame coordinates
+  const nsStyleTextOverflowSide* mStyle;
+  nscoord         mAscent; // baseline for the marker text in mRect
+  uint32_t        mIndex;
+};
+
+static void
+PaintTextShadowCallback(nsRenderingContext* aCtx,
+                        nsPoint aShadowOffset,
+                        const nscolor& aShadowColor,
+                        void* aData)
+{
+  reinterpret_cast<nsDisplayTextOverflowMarker*>(aData)->
+           PaintTextToContext(aCtx, aShadowOffset);
+}
+
+void
+nsDisplayTextOverflowMarker::Paint(nsDisplayListBuilder* aBuilder,
+                                   nsRenderingContext*   aCtx)
+{
+  nscolor foregroundColor = nsLayoutUtils::
+    GetColor(mFrame, eCSSProperty__webkit_text_fill_color);
+
+  // Paint the text-shadows for the overflow marker
+  nsLayoutUtils::PaintTextShadow(mFrame, aCtx, mRect, mVisibleRect,
+                                 foregroundColor, PaintTextShadowCallback,
+                                 (void*)this);
+  aCtx->ThebesContext()->SetColor(gfx::Color::FromABGR(foregroundColor));
+  PaintTextToContext(aCtx, nsPoint(0, 0));
+}
+
+void
+nsDisplayTextOverflowMarker::PaintTextToContext(nsRenderingContext* aCtx,
+                                                nsPoint aOffsetFromRect)
+{
+  WritingMode wm = mFrame->GetWritingMode();
+  nsPoint pt(mRect.x, mRect.y);
+  if (wm.IsVertical()) {
+    if (wm.IsVerticalLR()) {
+      pt.x = NSToCoordFloor(nsLayoutUtils::GetSnappedBaselineX(
+        mFrame, aCtx->ThebesContext(), pt.x, mAscent));
+    } else {
+      pt.x = NSToCoordFloor(nsLayoutUtils::GetSnappedBaselineX(
+        mFrame, aCtx->ThebesContext(), pt.x + mRect.width, -mAscent));
+    }
+  } else {
+    pt.y = NSToCoordFloor(nsLayoutUtils::GetSnappedBaselineY(
+      mFrame, aCtx->ThebesContext(), pt.y, mAscent));
+  }
+  pt += aOffsetFromRect;
+
+  if (mStyle->mType == NS_STYLE_TEXT_OVERFLOW_ELLIPSIS) {
+    gfxTextRun* textRun = GetEllipsisTextRun(mFrame);
+    if (textRun) {
+      NS_ASSERTION(!textRun->IsRightToLeft(),
+                   "Ellipsis textruns should always be LTR!");
+      gfxPoint gfxPt(pt.x, pt.y);
+      textRun->Draw(gfxTextRun::Range(textRun), gfxPt,
+                    gfxTextRun::DrawParams(aCtx->ThebesContext()));
+    }
+  } else {
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(mFrame);
+    nsLayoutUtils::DrawString(mFrame, *fm, aCtx, mStyle->mString.get(),
+                              mStyle->mString.Length(), pt);
+  }
+}
+
+TextOverflow::TextOverflow(nsDisplayListBuilder* aBuilder,
+                           nsIFrame* aBlockFrame)
+  : mContentArea(aBlockFrame->GetWritingMode(),
+                 aBlockFrame->GetContentRectRelativeToSelf(),
+                 aBlockFrame->GetSize())
+  , mBuilder(aBuilder)
+  , mBlock(aBlockFrame)
+  , mScrollableFrame(nsLayoutUtils::GetScrollableFrameFor(aBlockFrame))
+  , mBlockSize(aBlockFrame->GetSize())
+  , mBlockWM(aBlockFrame->GetWritingMode())
+  , mAdjustForPixelSnapping(false)
+{
+#ifdef MOZ_XUL
+  if (!mScrollableFrame) {
+    nsIAtom* pseudoType = aBlockFrame->StyleContext()->GetPseudo();
+    if (pseudoType == nsCSSAnonBoxes::mozXULAnonymousBlock) {
+      mScrollableFrame =
+        nsLayoutUtils::GetScrollableFrameFor(aBlockFrame->GetParent());
+      // nsXULScrollFrame::ClampAndSetBounds rounds to nearest pixels
+      // for RTL blocks (also for overflow:hidden), so we need to move
+      // the edges 1px outward in ExamineLineFrames to avoid triggering
+      // a text-overflow marker in this case.
+      mAdjustForPixelSnapping = !mBlockWM.IsBidiLTR();
+    }
+  }
+#endif
+  mCanHaveInlineAxisScrollbar = false;
+  if (mScrollableFrame) {
+    auto scrollbarStyle = mBlockWM.IsVertical() ?
+      mScrollableFrame->GetScrollbarStyles().mVertical :
+      mScrollableFrame->GetScrollbarStyles().mHorizontal;
+    mCanHaveInlineAxisScrollbar = scrollbarStyle != NS_STYLE_OVERFLOW_HIDDEN;
+    if (!mAdjustForPixelSnapping) {
+      // Scrolling to the end position can leave some text still overflowing due
+      // to pixel snapping behaviour in our scrolling code.
+      mAdjustForPixelSnapping = mCanHaveInlineAxisScrollbar;
+    }
+    // Use a null containerSize to convert a vector from logical to physical.
+    const nsSize nullContainerSize;
+    mContentArea.MoveBy(mBlockWM,
+                        LogicalPoint(mBlockWM,
+                                     mScrollableFrame->GetScrollPosition(),
+                                     nullContainerSize));
+    nsIFrame* scrollFrame = do_QueryFrame(mScrollableFrame);
+    scrollFrame->AddStateBits(NS_SCROLLFRAME_INVALIDATE_CONTENTS_ON_SCROLL);
+  }
+  uint8_t direction = aBlockFrame->StyleVisibility()->mDirection;
+  const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
+  if (mBlockWM.IsBidiLTR()) {
+    mIStart.Init(style->mTextOverflow.GetLeft(direction));
+    mIEnd.Init(style->mTextOverflow.GetRight(direction));
+  } else {
+    mIStart.Init(style->mTextOverflow.GetRight(direction));
+    mIEnd.Init(style->mTextOverflow.GetLeft(direction));
+  }
+  // The left/right marker string is setup in ExamineLineFrames when a line
+  // has overflow on that side.
+}
+
+/* static */ TextOverflow*
+TextOverflow::WillProcessLines(nsDisplayListBuilder*   aBuilder,
+                               nsIFrame*               aBlockFrame)
+{
+  if (!CanHaveTextOverflow(aBuilder, aBlockFrame)) {
+    return nullptr;
+  }
+  nsIScrollableFrame* scrollableFrame = nsLayoutUtils::GetScrollableFrameFor(aBlockFrame);
+  if (scrollableFrame && scrollableFrame->IsTransformingByAPZ()) {
+    // If the APZ is actively scrolling this, don't bother with markers.
+    return nullptr;
+  }
+  return new TextOverflow(aBuilder, aBlockFrame);
+}
+
+void
+TextOverflow::ExamineFrameSubtree(nsIFrame*       aFrame,
+                                  const LogicalRect& aContentArea,
+                                  const LogicalRect& aInsideMarkersArea,
+                                  FrameHashtable* aFramesToHide,
+                                  AlignmentEdges* aAlignmentEdges,
+                                  bool*           aFoundVisibleTextOrAtomic,
+                                  InnerClipEdges* aClippedMarkerEdges)
+{
+  const nsIAtom* frameType = aFrame->GetType();
+  if (frameType == nsGkAtoms::brFrame ||
+      frameType == nsGkAtoms::placeholderFrame) {
+    return;
+  }
+  const bool isAtomic = IsAtomicElement(aFrame, frameType);
+  if (aFrame->StyleVisibility()->IsVisible()) {
+    LogicalRect childRect =
+      GetLogicalScrollableOverflowRectRelativeToBlock(aFrame);
+    bool overflowIStart =
+      childRect.IStart(mBlockWM) < aContentArea.IStart(mBlockWM);
+    bool overflowIEnd =
+      childRect.IEnd(mBlockWM) > aContentArea.IEnd(mBlockWM);
+    if (overflowIStart) {
+      mIStart.mHasOverflow = true;
+    }
+    if (overflowIEnd) {
+      mIEnd.mHasOverflow = true;
+    }
+    if (isAtomic && ((mIStart.mActive && overflowIStart) ||
+                     (mIEnd.mActive && overflowIEnd))) {
+      aFramesToHide->PutEntry(aFrame);
+    } else if (isAtomic || frameType == nsGkAtoms::textFrame) {
+      AnalyzeMarkerEdges(aFrame, frameType, aInsideMarkersArea,
+                         aFramesToHide, aAlignmentEdges,
+                         aFoundVisibleTextOrAtomic,
+                         aClippedMarkerEdges);
+    }
+  }
+  if (isAtomic) {
+    return;
+  }
+
+  for (nsIFrame* child : aFrame->PrincipalChildList()) {
+    ExamineFrameSubtree(child, aContentArea, aInsideMarkersArea,
+                        aFramesToHide, aAlignmentEdges,
+                        aFoundVisibleTextOrAtomic,
+                        aClippedMarkerEdges);
+  }
+}
+
+void
+TextOverflow::AnalyzeMarkerEdges(nsIFrame*       aFrame,
+                                 const nsIAtom*  aFrameType,
+                                 const LogicalRect& aInsideMarkersArea,
+                                 FrameHashtable* aFramesToHide,
+                                 AlignmentEdges* aAlignmentEdges,
+                                 bool*           aFoundVisibleTextOrAtomic,
+                                 InnerClipEdges* aClippedMarkerEdges)
+{
+  LogicalRect borderRect(mBlockWM,
+                         nsRect(aFrame->GetOffsetTo(mBlock),
+                                aFrame->GetSize()),
+                         mBlockSize);
+  nscoord istartOverlap = std::max(
+    aInsideMarkersArea.IStart(mBlockWM) - borderRect.IStart(mBlockWM), 0);
+  nscoord iendOverlap = std::max(
+    borderRect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM), 0);
+  bool insideIStartEdge =
+    aInsideMarkersArea.IStart(mBlockWM) <= borderRect.IEnd(mBlockWM);
+  bool insideIEndEdge =
+    borderRect.IStart(mBlockWM) <= aInsideMarkersArea.IEnd(mBlockWM);
+
+  if (istartOverlap > 0) {
+    aClippedMarkerEdges->AccumulateIStart(mBlockWM, borderRect);
+    if (!mIStart.mActive) {
+      istartOverlap = 0;
+    }
+  }
+  if (iendOverlap > 0) {
+    aClippedMarkerEdges->AccumulateIEnd(mBlockWM, borderRect);
+    if (!mIEnd.mActive) {
+      iendOverlap = 0;
+    }
+  }
+
+  if ((istartOverlap > 0 && insideIStartEdge) ||
+      (iendOverlap > 0 && insideIEndEdge)) {
+    if (aFrameType == nsGkAtoms::textFrame) {
+      if (aInsideMarkersArea.IStart(mBlockWM) <
+          aInsideMarkersArea.IEnd(mBlockWM)) {
+        // a clipped text frame and there is some room between the markers
+        nscoord snappedIStart, snappedIEnd;
+        auto textFrame = static_cast<nsTextFrame*>(aFrame);
+        bool isFullyClipped = mBlockWM.IsBidiLTR() ?
+          IsFullyClipped(textFrame, istartOverlap, iendOverlap,
+                         &snappedIStart, &snappedIEnd) :
+          IsFullyClipped(textFrame, iendOverlap, istartOverlap,
+                         &snappedIEnd, &snappedIStart);
+        if (!isFullyClipped) {
+          LogicalRect snappedRect = borderRect;
+          if (istartOverlap > 0) {
+            snappedRect.IStart(mBlockWM) += snappedIStart;
+            snappedRect.ISize(mBlockWM) -= snappedIStart;
+          }
+          if (iendOverlap > 0) {
+            snappedRect.ISize(mBlockWM) -= snappedIEnd;
+          }
+          aAlignmentEdges->Accumulate(mBlockWM, snappedRect);
+          *aFoundVisibleTextOrAtomic = true;
+        }
+      }
+    } else {
+      aFramesToHide->PutEntry(aFrame);
+    }
+  } else if (!insideIStartEdge || !insideIEndEdge) {
+    // frame is outside
+    if (IsAtomicElement(aFrame, aFrameType)) {
+      aFramesToHide->PutEntry(aFrame);
+    }
+  } else {
+    // frame is inside
+    aAlignmentEdges->Accumulate(mBlockWM, borderRect);
+    *aFoundVisibleTextOrAtomic = true;
+  }
+}
+
+void
+TextOverflow::ExamineLineFrames(nsLineBox*      aLine,
+                                FrameHashtable* aFramesToHide,
+                                AlignmentEdges* aAlignmentEdges)
+{
+  // No ellipsing for 'clip' style.
+  bool suppressIStart = mIStart.mStyle->mType == NS_STYLE_TEXT_OVERFLOW_CLIP;
+  bool suppressIEnd = mIEnd.mStyle->mType == NS_STYLE_TEXT_OVERFLOW_CLIP;
+  if (mCanHaveInlineAxisScrollbar) {
+    LogicalPoint pos(mBlockWM, mScrollableFrame->GetScrollPosition(),
+                     mBlockSize);
+    LogicalRect scrollRange(mBlockWM, mScrollableFrame->GetScrollRange(),
+                            mBlockSize);
+    // No ellipsing when nothing to scroll to on that side (this includes
+    // overflow:auto that doesn't trigger a horizontal scrollbar).
+    if (pos.I(mBlockWM) <= scrollRange.IStart(mBlockWM)) {
+      suppressIStart = true;
+    }
+    if (pos.I(mBlockWM) >= scrollRange.IEnd(mBlockWM)) {
+      suppressIEnd = true;
+    }
+  }
+
+  LogicalRect contentArea = mContentArea;
+  const nscoord scrollAdjust = mAdjustForPixelSnapping ?
+    mBlock->PresContext()->AppUnitsPerDevPixel() : 0;
+  InflateIStart(mBlockWM, &contentArea, scrollAdjust);
+  InflateIEnd(mBlockWM, &contentArea, scrollAdjust);
+  LogicalRect lineRect(mBlockWM, aLine->GetScrollableOverflowArea(),
+                       mBlockSize);
+  const bool istartOverflow =
+    !suppressIStart && lineRect.IStart(mBlockWM) < contentArea.IStart(mBlockWM);
+  const bool iendOverflow =
+    !suppressIEnd && lineRect.IEnd(mBlockWM) > contentArea.IEnd(mBlockWM);
+  if (!istartOverflow && !iendOverflow) {
+    // The line does not overflow on a side we should ellipsize.
+    return;
+  }
+
+  int pass = 0;
+  bool retryEmptyLine = true;
+  bool guessIStart = istartOverflow;
+  bool guessIEnd = iendOverflow;
+  mIStart.mActive = istartOverflow;
+  mIEnd.mActive = iendOverflow;
+  bool clippedIStartMarker = false;
+  bool clippedIEndMarker = false;
+  do {
+    // Setup marker strings as needed.
+    if (guessIStart) {
+      mIStart.SetupString(mBlock);
+    }
+    if (guessIEnd) {
+      mIEnd.SetupString(mBlock);
+    }
+    
+    // If there is insufficient space for both markers then keep the one on the
+    // end side per the block's 'direction'.
+    nscoord istartMarkerISize = mIStart.mActive ? mIStart.mISize : 0;
+    nscoord iendMarkerISize = mIEnd.mActive ? mIEnd.mISize : 0;
+    if (istartMarkerISize && iendMarkerISize &&
+        istartMarkerISize + iendMarkerISize > contentArea.ISize(mBlockWM)) {
+      istartMarkerISize = 0;
+    }
+
+    // Calculate the area between the potential markers aligned at the
+    // block's edge.
+    LogicalRect insideMarkersArea = mContentArea;
+    if (guessIStart) {
+      InflateIStart(mBlockWM, &insideMarkersArea, -istartMarkerISize);
+    }
+    if (guessIEnd) {
+      InflateIEnd(mBlockWM, &insideMarkersArea, -iendMarkerISize);
+    }
+
+    // Analyze the frames on aLine for the overflow situation at the content
+    // edges and at the edges of the area between the markers.
+    bool foundVisibleTextOrAtomic = false;
+    int32_t n = aLine->GetChildCount();
+    nsIFrame* child = aLine->mFirstChild;
+    InnerClipEdges clippedMarkerEdges;
+    for (; n-- > 0; child = child->GetNextSibling()) {
+      ExamineFrameSubtree(child, contentArea, insideMarkersArea,
+                          aFramesToHide, aAlignmentEdges,
+                          &foundVisibleTextOrAtomic,
+                          &clippedMarkerEdges);
+    }
+    if (!foundVisibleTextOrAtomic && retryEmptyLine) {
+      aAlignmentEdges->mAssigned = false;
+      aFramesToHide->Clear();
+      pass = -1;
+      if (mIStart.IsNeeded() && mIStart.mActive && !clippedIStartMarker) {
+        if (clippedMarkerEdges.mAssignedIStart &&
+            clippedMarkerEdges.mIStart > mContentArea.IStart(mBlockWM)) {
+          mIStart.mISize =
+            clippedMarkerEdges.mIStart - mContentArea.IStart(mBlockWM);
+          NS_ASSERTION(mIStart.mISize < mIStart.mIntrinsicISize,
+                      "clipping a marker should make it strictly smaller");
+          clippedIStartMarker = true;
+        } else {
+          mIStart.mActive = guessIStart = false;
+        }
+        continue;
+      }
+      if (mIEnd.IsNeeded() && mIEnd.mActive && !clippedIEndMarker) {
+        if (clippedMarkerEdges.mAssignedIEnd &&
+            mContentArea.IEnd(mBlockWM) > clippedMarkerEdges.mIEnd) {
+          mIEnd.mISize = mContentArea.IEnd(mBlockWM) - clippedMarkerEdges.mIEnd;
+          NS_ASSERTION(mIEnd.mISize < mIEnd.mIntrinsicISize,
+                      "clipping a marker should make it strictly smaller");
+          clippedIEndMarker = true;
+        } else {
+          mIEnd.mActive = guessIEnd = false;
+        }
+        continue;
+      }
+      // The line simply has no visible content even without markers,
+      // so examine the line again without suppressing markers.
+      retryEmptyLine = false;
+      mIStart.mISize = mIStart.mIntrinsicISize;
+      mIStart.mActive = guessIStart = istartOverflow;
+      mIEnd.mISize = mIEnd.mIntrinsicISize;
+      mIEnd.mActive = guessIEnd = iendOverflow;
+      continue;
+    }
+    if (guessIStart == (mIStart.mActive && mIStart.IsNeeded()) &&
+        guessIEnd == (mIEnd.mActive && mIEnd.IsNeeded())) {
+      break;
+    } else {
+      guessIStart = mIStart.mActive && mIStart.IsNeeded();
+      guessIEnd = mIEnd.mActive && mIEnd.IsNeeded();
+      mIStart.Reset();
+      mIEnd.Reset();
+      aFramesToHide->Clear();
+    }
+    NS_ASSERTION(pass == 0, "2nd pass should never guess wrong");
+  } while (++pass != 2);
+  if (!istartOverflow || !mIStart.mActive) {
+    mIStart.Reset();
+  }
+  if (!iendOverflow || !mIEnd.mActive) {
+    mIEnd.Reset();
+  }
+}
+
+void
+TextOverflow::ProcessLine(const nsDisplayListSet& aLists,
+                          nsLineBox*              aLine)
+{
+  NS_ASSERTION(mIStart.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP ||
+               mIEnd.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP,
+               "TextOverflow with 'clip' for both sides");
+  mIStart.Reset();
+  mIStart.mActive = mIStart.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP;
+  mIEnd.Reset();
+  mIEnd.mActive = mIEnd.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP;
+
+  FrameHashtable framesToHide(64);
+  AlignmentEdges alignmentEdges;
+  ExamineLineFrames(aLine, &framesToHide, &alignmentEdges);
+  bool needIStart = mIStart.IsNeeded();
+  bool needIEnd = mIEnd.IsNeeded();
+  if (!needIStart && !needIEnd) {
+    return;
+  }
+  NS_ASSERTION(mIStart.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP ||
+               !needIStart, "left marker for 'clip'");
+  NS_ASSERTION(mIEnd.mStyle->mType != NS_STYLE_TEXT_OVERFLOW_CLIP ||
+               !needIEnd, "right marker for 'clip'");
+
+  // If there is insufficient space for both markers then keep the one on the
+  // end side per the block's 'direction'.
+  if (needIStart && needIEnd &&
+      mIStart.mISize + mIEnd.mISize > mContentArea.ISize(mBlockWM)) {
+    needIStart = false;
+  }
+  LogicalRect insideMarkersArea = mContentArea;
+  if (needIStart) {
+    InflateIStart(mBlockWM, &insideMarkersArea, -mIStart.mISize);
+  }
+  if (needIEnd) {
+    InflateIEnd(mBlockWM, &insideMarkersArea, -mIEnd.mISize);
+  }
+  if (!mCanHaveInlineAxisScrollbar && alignmentEdges.mAssigned) {
+    LogicalRect alignmentRect(mBlockWM, alignmentEdges.mIStart,
+                              insideMarkersArea.BStart(mBlockWM),
+                              alignmentEdges.ISize(), 1);
+    insideMarkersArea.IntersectRect(insideMarkersArea, alignmentRect);
+  }
+
+  // Clip and remove display items as needed at the final marker edges.
+  nsDisplayList* lists[] = { aLists.Content(), aLists.PositionedDescendants() };
+  for (uint32_t i = 0; i < ArrayLength(lists); ++i) {
+    PruneDisplayListContents(lists[i], framesToHide, insideMarkersArea);
+  }
+  CreateMarkers(aLine, needIStart, needIEnd, insideMarkersArea);
+}
+
+void
+TextOverflow::PruneDisplayListContents(nsDisplayList* aList,
+                                       const FrameHashtable& aFramesToHide,
+                                       const LogicalRect& aInsideMarkersArea)
+{
+  nsDisplayList saved;
+  nsDisplayItem* item;
+  while ((item = aList->RemoveBottom())) {
+    nsIFrame* itemFrame = item->Frame();
+    if (IsFrameDescendantOfAny(itemFrame, aFramesToHide, mBlock)) {
+      item->~nsDisplayItem();
+      continue;
+    }
+
+    nsDisplayList* wrapper = item->GetSameCoordinateSystemChildren();
+    if (wrapper) {
+      if (!itemFrame || GetSelfOrNearestBlock(itemFrame) == mBlock) {
+        PruneDisplayListContents(wrapper, aFramesToHide, aInsideMarkersArea);
+      }
+    }
+
+    nsCharClipDisplayItem* charClip = itemFrame ? 
+      nsCharClipDisplayItem::CheckCast(item) : nullptr;
+    if (charClip && GetSelfOrNearestBlock(itemFrame) == mBlock) {
+      LogicalRect rect =
+        GetLogicalScrollableOverflowRectRelativeToBlock(itemFrame);
+      if (mIStart.IsNeeded()) {
+        nscoord istart =
+          aInsideMarkersArea.IStart(mBlockWM) - rect.IStart(mBlockWM);
+        if (istart > 0) {
+          (mBlockWM.IsBidiLTR() ?
+           charClip->mVisIStartEdge : charClip->mVisIEndEdge) = istart;
+        }
+      }
+      if (mIEnd.IsNeeded()) {
+        nscoord iend = rect.IEnd(mBlockWM) - aInsideMarkersArea.IEnd(mBlockWM);
+        if (iend > 0) {
+          (mBlockWM.IsBidiLTR() ?
+           charClip->mVisIEndEdge : charClip->mVisIStartEdge) = iend;
+        }
+      }
+    }
+
+    saved.AppendToTop(item);
+  }
+  aList->AppendToTop(&saved);
+}
+
+/* static */ bool
+TextOverflow::HasClippedOverflow(nsIFrame* aBlockFrame)
+{
+  const nsStyleTextReset* style = aBlockFrame->StyleTextReset();
+  return style->mTextOverflow.mLeft.mType == NS_STYLE_TEXT_OVERFLOW_CLIP &&
+         style->mTextOverflow.mRight.mType == NS_STYLE_TEXT_OVERFLOW_CLIP;
+}
+
+/* static */ bool
+TextOverflow::CanHaveTextOverflow(nsDisplayListBuilder* aBuilder,
+                                  nsIFrame*             aBlockFrame)
+{
+  // Nothing to do for text-overflow:clip or if 'overflow-x/y:visible' or if
+  // we're just building items for event processing or frame visibility.
+  if (HasClippedOverflow(aBlockFrame) ||
+      IsInlineAxisOverflowVisible(aBlockFrame) ||
+      aBuilder->IsForEventDelivery() ||
+      aBuilder->IsForFrameVisibility()) {
+    return false;
+  }
+
+  // Skip ComboboxControlFrame because it would clip the drop-down arrow.
+  // Its anon block inherits 'text-overflow' and does what is expected.
+  if (aBlockFrame->GetType() == nsGkAtoms::comboboxControlFrame) {
+    return false;
+  }
+
+  // Inhibit the markers if a descendant content owns the caret.
+  RefPtr<nsCaret> caret = aBlockFrame->PresContext()->PresShell()->GetCaret();
+  if (caret && caret->IsVisible()) {
+    nsCOMPtr<nsISelection> domSelection = caret->GetSelection();
+    if (domSelection) {
+      nsCOMPtr<nsIDOMNode> node;
+      domSelection->GetFocusNode(getter_AddRefs(node));
+      nsCOMPtr<nsIContent> content = do_QueryInterface(node);
+      if (content && nsContentUtils::ContentIsDescendantOf(content,
+                       aBlockFrame->GetContent())) {
+        return false;
+      }
+    }
+  }
+  return true;
+}
+
+void
+TextOverflow::CreateMarkers(const nsLineBox* aLine,
+                            bool aCreateIStart, bool aCreateIEnd,
+                            const mozilla::LogicalRect& aInsideMarkersArea)
+{
+  if (aCreateIStart) {
+    DisplayListClipState::AutoSaveRestore clipState(mBuilder);
+
+    LogicalRect markerLogicalRect(
+      mBlockWM, aInsideMarkersArea.IStart(mBlockWM) - mIStart.mIntrinsicISize,
+      aLine->BStart(), mIStart.mIntrinsicISize, aLine->BSize());
+    nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
+    nsRect markerRect =
+      markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
+    ClipMarker(mContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
+               markerRect, clipState);
+    nsDisplayItem* marker = new (mBuilder)
+      nsDisplayTextOverflowMarker(mBuilder, mBlock, markerRect,
+                                  aLine->GetLogicalAscent(), mIStart.mStyle, 0);
+    mMarkerList.AppendNewToTop(marker);
+  }
+
+  if (aCreateIEnd) {
+    DisplayListClipState::AutoSaveRestore clipState(mBuilder);
+
+    LogicalRect markerLogicalRect(
+      mBlockWM, aInsideMarkersArea.IEnd(mBlockWM), aLine->BStart(),
+      mIEnd.mIntrinsicISize, aLine->BSize());
+    nsPoint offset = mBuilder->ToReferenceFrame(mBlock);
+    nsRect markerRect =
+      markerLogicalRect.GetPhysicalRect(mBlockWM, mBlockSize) + offset;
+    ClipMarker(mContentArea.GetPhysicalRect(mBlockWM, mBlockSize) + offset,
+               markerRect, clipState);
+    nsDisplayItem* marker = new (mBuilder)
+      nsDisplayTextOverflowMarker(mBuilder, mBlock, markerRect,
+                                  aLine->GetLogicalAscent(), mIEnd.mStyle, 1);
+    mMarkerList.AppendNewToTop(marker);
+  }
+}
+
+void
+TextOverflow::Marker::SetupString(nsIFrame* aFrame)
+{
+  if (mInitialized) {
+    return;
+  }
+
+  if (mStyle->mType == NS_STYLE_TEXT_OVERFLOW_ELLIPSIS) {
+    gfxTextRun* textRun = GetEllipsisTextRun(aFrame);
+    if (textRun) {
+      mISize = textRun->GetAdvanceWidth();
+    } else {
+      mISize = 0;
+    }
+  } else {
+    nsRenderingContext rc(
+      aFrame->PresContext()->PresShell()->CreateReferenceRenderingContext());
+    RefPtr<nsFontMetrics> fm =
+      nsLayoutUtils::GetInflatedFontMetricsForFrame(aFrame);
+    mISize = nsLayoutUtils::AppUnitWidthOfStringBidi(mStyle->mString, aFrame,
+                                                     *fm, rc);
+  }
+  mIntrinsicISize = mISize;
+  mInitialized = true;
+}
+
+} // namespace css
+} // namespace mozilla