webkitgtk-2.16.5HEADwebkitgtk-2.16.5master

1 files changed, 874 insertions, 742 deletions

diff --git a/Source/WebCore/rendering/RenderBlockLineLayout.cpp b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
index 3e546abec..085937b57 100644
--- a/Source/WebCore/rendering/RenderBlockLineLayout.cpp
+++ b/Source/WebCore/rendering/RenderBlockLineLayout.cpp
@@ -26,29 +26,28 @@
 
 #include "AXObjectCache.h"
 #include "BidiResolver.h"
-#include "BreakingContextInlineHeaders.h"
+#include "BreakingContext.h"
 #include "FloatingObjects.h"
 #include "InlineElementBox.h"
 #include "InlineIterator.h"
 #include "InlineTextBox.h"
+#include "InlineTextBoxStyle.h"
 #include "LineLayoutState.h"
 #include "Logging.h"
 #include "RenderBlockFlow.h"
 #include "RenderFlowThread.h"
 #include "RenderLineBreak.h"
 #include "RenderRegion.h"
+#include "RenderRubyBase.h"
+#include "RenderRubyText.h"
 #include "RenderView.h"
+#include "SVGRootInlineBox.h"
 #include "Settings.h"
 #include "SimpleLineLayoutFunctions.h"
 #include "TrailingFloatsRootInlineBox.h"
 #include "VerticalPositionCache.h"
-#include <wtf/RefCountedLeakCounter.h>
 #include <wtf/StdLibExtras.h>
 
-#if ENABLE(SVG)
-#include "SVGRootInlineBox.h"
-#endif
-
 namespace WebCore {
 
 static void determineDirectionality(TextDirection& dir, InlineIterator iter)
@@ -71,50 +70,50 @@ static void determineDirectionality(TextDirection& dir, InlineIterator iter)
     }
 }
 
-inline BidiRun* createRun(int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
+inline std::unique_ptr<BidiRun> createRun(int start, int end, RenderObject& obj, InlineBidiResolver& resolver)
 {
-    ASSERT(obj);
-    return new BidiRun(start, end, *obj, resolver.context(), resolver.dir());
+    return std::make_unique<BidiRun>(start, end, obj, resolver.context(), resolver.dir());
 }
 
-void RenderBlockFlow::appendRunsForObject(BidiRunList<BidiRun>& runs, int start, int end, RenderObject* obj, InlineBidiResolver& resolver)
+void RenderBlockFlow::appendRunsForObject(BidiRunList<BidiRun>* runs, int start, int end, RenderObject& obj, InlineBidiResolver& resolver)
 {
     if (start > end || shouldSkipCreatingRunsForObject(obj))
         return;
 
-    LineMidpointState& lineMidpointState = resolver.midpointState();
-    bool haveNextMidpoint = (lineMidpointState.currentMidpoint() < lineMidpointState.numMidpoints());
-    InlineIterator nextMidpoint;
-    if (haveNextMidpoint)
-        nextMidpoint = lineMidpointState.midpoints()[lineMidpointState.currentMidpoint()];
-    if (lineMidpointState.betweenMidpoints()) {
-        if (!(haveNextMidpoint && nextMidpoint.renderer() == obj))
+    LineWhitespaceCollapsingState& lineWhitespaceCollapsingState = resolver.whitespaceCollapsingState();
+    bool haveNextTransition = (lineWhitespaceCollapsingState.currentTransition() < lineWhitespaceCollapsingState.numTransitions());
+    InlineIterator nextTransition;
+    if (haveNextTransition)
+        nextTransition = lineWhitespaceCollapsingState.transitions()[lineWhitespaceCollapsingState.currentTransition()];
+    if (lineWhitespaceCollapsingState.betweenTransitions()) {
+        if (!haveNextTransition || (&obj != nextTransition.renderer()))
             return;
         // This is a new start point. Stop ignoring objects and
         // adjust our start.
-        lineMidpointState.setBetweenMidpoints(false);
-        start = nextMidpoint.offset();
-        lineMidpointState.incrementCurrentMidpoint();
-        if (start < end)
-            return appendRunsForObject(runs, start, end, obj, resolver);
+        start = nextTransition.offset();
+        lineWhitespaceCollapsingState.incrementCurrentTransition();
+        if (start < end) {
+            appendRunsForObject(runs, start, end, obj, resolver);
+            return;
+        }
     } else {
-        if (!haveNextMidpoint || (obj != nextMidpoint.renderer())) {
-            runs.addRun(createRun(start, end, obj, resolver));
+        if (!haveNextTransition || (&obj != nextTransition.renderer())) {
+            if (runs)
+                runs->appendRun(createRun(start, end, obj, resolver));
             return;
         }
 
-        // An end midpoint has been encountered within our object.  We
-        // need to go ahead and append a run with our endpoint.
-        if (static_cast<int>(nextMidpoint.offset() + 1) <= end) {
-            lineMidpointState.setBetweenMidpoints(true);
-            lineMidpointState.incrementCurrentMidpoint();
-            if (nextMidpoint.offset() != UINT_MAX) { // UINT_MAX means stop at the object and don't include any of it.
-                if (static_cast<int>(nextMidpoint.offset() + 1) > start)
-                    runs.addRun(createRun(start, nextMidpoint.offset() + 1, obj, resolver));
-                return appendRunsForObject(runs, nextMidpoint.offset() + 1, end, obj, resolver);
-            }
-        } else
-           runs.addRun(createRun(start, end, obj, resolver));
+        // An end transition has been encountered within our object. We need to append a run with our endpoint.
+        if (static_cast<int>(nextTransition.offset() + 1) <= end) {
+            lineWhitespaceCollapsingState.incrementCurrentTransition();
+            // The end of the line is before the object we're inspecting. Skip everything and return
+            if (nextTransition.refersToEndOfPreviousNode())
+                return;
+            if (static_cast<int>(nextTransition.offset() + 1) > start && runs)
+                runs->appendRun(createRun(start, nextTransition.offset() + 1, obj, resolver));
+            appendRunsForObject(runs, nextTransition.offset() + 1, end, obj, resolver);
+        } else if (runs)
+            runs->appendRun(createRun(start, end, obj, resolver));
     }
 }
 
@@ -127,51 +126,51 @@ RootInlineBox* RenderBlockFlow::createAndAppendRootInlineBox()
 {
     auto newRootBox = createRootInlineBox();
     RootInlineBox* rootBox = newRootBox.get();
-    m_lineBoxes.appendLineBox(std::move(newRootBox));
+    m_lineBoxes.appendLineBox(WTFMove(newRootBox));
 
     if (UNLIKELY(AXObjectCache::accessibilityEnabled()) && firstRootBox() == rootBox) {
         if (AXObjectCache* cache = document().existingAXObjectCache())
-            cache->recomputeIsIgnored(this);
+            cache->recomputeDeferredIsIgnored(*this);
     }
 
     return rootBox;
 }
 
-static inline InlineBox* createInlineBoxForRenderer(RenderObject* obj, bool isRootLineBox, bool isOnlyRun = false)
+static inline InlineBox* createInlineBoxForRenderer(RenderObject* renderer, bool isRootLineBox, bool isOnlyRun = false)
 {
     if (isRootLineBox)
-        return toRenderBlockFlow(obj)->createAndAppendRootInlineBox();
+        return downcast<RenderBlockFlow>(*renderer).createAndAppendRootInlineBox();
 
-    if (obj->isText())
-        return toRenderText(obj)->createInlineTextBox();
+    if (is<RenderText>(*renderer))
+        return downcast<RenderText>(*renderer).createInlineTextBox();
 
-    if (obj->isBox()) {
+    if (is<RenderBox>(*renderer)) {
         // FIXME: This is terrible. This branch returns an *owned* pointer!
-        return toRenderBox(obj)->createInlineBox().release();
+        return downcast<RenderBox>(*renderer).createInlineBox().release();
     }
 
-    if (obj->isLineBreak()) {
+    if (is<RenderLineBreak>(*renderer)) {
         // FIXME: This is terrible. This branch returns an *owned* pointer!
-        auto inlineBox = toRenderLineBreak(obj)->createInlineBox().release();
+        auto inlineBox = downcast<RenderLineBreak>(*renderer).createInlineBox().release();
         // We only treat a box as text for a <br> if we are on a line by ourself or in strict mode
         // (Note the use of strict mode. In "almost strict" mode, we don't treat the box for <br> as text.)
-        inlineBox->setBehavesLikeText(isOnlyRun || obj->document().inNoQuirksMode() || obj->isLineBreakOpportunity());
+        inlineBox->setBehavesLikeText(isOnlyRun || renderer->document().inNoQuirksMode() || renderer->isLineBreakOpportunity());
         return inlineBox;
     }
 
-    return toRenderInline(obj)->createAndAppendInlineFlowBox();
+    return downcast<RenderInline>(*renderer).createAndAppendInlineFlowBox();
 }
 
 static inline void dirtyLineBoxesForRenderer(RenderObject& renderer, bool fullLayout)
 {
-    if (renderer.isText()) {
-        RenderText& renderText = toRenderText(renderer);
+    if (is<RenderText>(renderer)) {
+        RenderText& renderText = downcast<RenderText>(renderer);
         updateCounterIfNeeded(renderText);
         renderText.dirtyLineBoxes(fullLayout);
-    } else if (renderer.isLineBreak())
-        toRenderLineBreak(renderer).dirtyLineBoxes(fullLayout);
+    } else if (is<RenderLineBreak>(renderer))
+        downcast<RenderLineBreak>(renderer).dirtyLineBoxes(fullLayout);
     else
-        toRenderInline(renderer).dirtyLineBoxes(fullLayout);
+        downcast<RenderInline>(renderer).dirtyLineBoxes(fullLayout);
 }
 
 static bool parentIsConstructedOrHaveNext(InlineFlowBox* parentBox)
@@ -184,21 +183,21 @@ static bool parentIsConstructedOrHaveNext(InlineFlowBox* parentBox)
     return false;
 }
 
-InlineFlowBox* RenderBlockFlow::createLineBoxes(RenderObject* obj, const LineInfo& lineInfo, InlineBox* childBox, bool startNewSegment)
+InlineFlowBox* RenderBlockFlow::createLineBoxes(RenderObject* obj, const LineInfo& lineInfo, InlineBox* childBox)
 {
     // See if we have an unconstructed line box for this object that is also
     // the last item on the line.
     unsigned lineDepth = 1;
-    InlineFlowBox* parentBox = 0;
-    InlineFlowBox* result = 0;
+    InlineFlowBox* parentBox = nullptr;
+    InlineFlowBox* result = nullptr;
     bool hasDefaultLineBoxContain = style().lineBoxContain() == RenderStyle::initialLineBoxContain();
     do {
-        ASSERT_WITH_SECURITY_IMPLICATION(obj->isRenderInline() || obj == this);
+        ASSERT_WITH_SECURITY_IMPLICATION(is<RenderInline>(*obj) || obj == this);
 
-        RenderInline* inlineFlow = (obj != this) ? toRenderInline(obj) : 0;
+        RenderInline* inlineFlow = obj != this ? downcast<RenderInline>(obj) : nullptr;
 
         // Get the last box we made for this render object.
-        parentBox = inlineFlow ? inlineFlow->lastLineBox() : toRenderBlockFlow(obj)->lastRootBox();
+        parentBox = inlineFlow ? inlineFlow->lastLineBox() : downcast<RenderBlockFlow>(*obj).lastRootBox();
 
         // If this box or its ancestor is constructed then it is from a previous line, and we need
         // to make a new box for our line.  If this box or its ancestor is unconstructed but it has
@@ -207,14 +206,12 @@ InlineFlowBox* RenderBlockFlow::createLineBoxes(RenderObject* obj, const LineInf
         // the same line (this can happen with very fancy language mixtures).
         bool constructedNewBox = false;
         bool allowedToConstructNewBox = !hasDefaultLineBoxContain || !inlineFlow || inlineFlow->alwaysCreateLineBoxes();
-        bool mustCreateBoxesToRoot = startNewSegment && !(parentBox && parentBox->isRootInlineBox());
-        bool canUseExistingParentBox = parentBox && !parentIsConstructedOrHaveNext(parentBox) && !mustCreateBoxesToRoot;
+        bool canUseExistingParentBox = parentBox && !parentIsConstructedOrHaveNext(parentBox);
         if (allowedToConstructNewBox && !canUseExistingParentBox) {
             // We need to make a new box for this render object.  Once
             // made, we need to place it at the end of the current line.
             InlineBox* newBox = createInlineBoxForRenderer(obj, obj == this);
-            ASSERT_WITH_SECURITY_IMPLICATION(newBox->isInlineFlowBox());
-            parentBox = toInlineFlowBox(newBox);
+            parentBox = downcast<InlineFlowBox>(newBox);
             parentBox->setIsFirstLine(lineInfo.isFirstLine());
             parentBox->setIsHorizontal(isHorizontalWritingMode());
             if (!hasDefaultLineBoxContain)
@@ -264,10 +261,10 @@ static bool reachedEndOfTextRenderer(const BidiRunList<BidiRun>& bidiRuns)
     if (!run)
         return true;
     unsigned pos = run->stop();
-    const RenderObject& r = run->renderer();
-    if (!r.isText())
+    const RenderObject& renderer = run->renderer();
+    if (!is<RenderText>(renderer))
         return false;
-    const RenderText& renderText = toRenderText(r);
+    const RenderText& renderText = downcast<RenderText>(renderer);
     unsigned length = renderText.textLength();
     if (pos >= length)
         return true;
@@ -284,6 +281,7 @@ RootInlineBox* RenderBlockFlow::constructLine(BidiRunList<BidiRun>& bidiRuns, co
     bool rootHasSelectedChildren = false;
     InlineFlowBox* parentBox = 0;
     int runCount = bidiRuns.runCount() - lineInfo.runsFromLeadingWhitespace();
+    
     for (BidiRun* r = bidiRuns.firstRun(); r; r = r->next()) {
         // Create a box for our object.
         bool isOnlyRun = (runCount == 1);
@@ -294,24 +292,20 @@ RootInlineBox* RenderBlockFlow::constructLine(BidiRunList<BidiRun>& bidiRuns, co
             continue;
 
         InlineBox* box = createInlineBoxForRenderer(&r->renderer(), false, isOnlyRun);
-        r->setBox(*box);
+        r->setBox(box);
 
         if (!rootHasSelectedChildren && box->renderer().selectionState() != RenderObject::SelectionNone)
             rootHasSelectedChildren = true;
-
+        
         // If we have no parent box yet, or if the run is not simply a sibling,
         // then we need to construct inline boxes as necessary to properly enclose the
         // run's inline box. Segments can only be siblings at the root level, as
         // they are positioned separately.
-#if ENABLE(CSS_SHAPES)
-        bool runStartsSegment = r->m_startsSegment;
-#else
-        bool runStartsSegment = false;
-#endif
-        if (!parentBox || &parentBox->renderer() != r->renderer().parent() || runStartsSegment)
+        if (!parentBox || &parentBox->renderer() != r->renderer().parent()) {
             // Create new inline boxes all the way back to the appropriate insertion point.
-            parentBox = createLineBoxes(r->renderer().parent(), lineInfo, box, runStartsSegment);
-        else {
+            RenderObject* parentToUse = r->renderer().parent();
+            parentBox = createLineBoxes(parentToUse, lineInfo, box);
+        } else {
             // Append the inline box to this line.
             parentBox->addToLine(box);
         }
@@ -319,13 +313,13 @@ RootInlineBox* RenderBlockFlow::constructLine(BidiRunList<BidiRun>& bidiRuns, co
         bool visuallyOrdered = r->renderer().style().rtlOrdering() == VisualOrder;
         box->setBidiLevel(r->level());
 
-        if (box->isInlineTextBox()) {
-            InlineTextBox* text = toInlineTextBox(box);
-            text->setStart(r->m_start);
-            text->setLen(r->m_stop - r->m_start);
-            text->setDirOverride(r->dirOverride(visuallyOrdered));
+        if (is<InlineTextBox>(*box)) {
+            auto& textBox = downcast<InlineTextBox>(*box);
+            textBox.setStart(r->m_start);
+            textBox.setLen(r->m_stop - r->m_start);
+            textBox.setDirOverride(r->dirOverride(visuallyOrdered));
             if (r->m_hasHyphen)
-                text->setHasHyphen(true);
+                textBox.setHasHyphen(true);
         }
     }
 
@@ -342,7 +336,7 @@ RootInlineBox* RenderBlockFlow::constructLine(BidiRunList<BidiRun>& bidiRuns, co
     // paint borders/margins/padding.  This knowledge will ultimately be used when
     // we determine the horizontal positions and widths of all the inline boxes on
     // the line.
-    bool isLogicallyLastRunWrapped = bidiRuns.logicallyLastRun()->renderer().isText() ? !reachedEndOfTextRenderer(bidiRuns) : true;
+    bool isLogicallyLastRunWrapped = bidiRuns.logicallyLastRun()->renderer().isText() ? !reachedEndOfTextRenderer(bidiRuns) : !is<RenderInline>(bidiRuns.logicallyLastRun()->renderer());
     lastRootBox()->determineSpacingForFlowBoxes(lineInfo.isLastLine(), isLogicallyLastRunWrapped, &bidiRuns.logicallyLastRun()->renderer());
 
     // Now mark the line boxes as being constructed.
@@ -355,6 +349,12 @@ RootInlineBox* RenderBlockFlow::constructLine(BidiRunList<BidiRun>& bidiRuns, co
 ETextAlign RenderBlockFlow::textAlignmentForLine(bool endsWithSoftBreak) const
 {
     ETextAlign alignment = style().textAlign();
+#if ENABLE(CSS3_TEXT)
+    TextJustify textJustify = style().textJustify();
+    if (alignment == JUSTIFY && textJustify == TextJustifyNone)
+        return style().direction() == LTR ? LEFT : RIGHT;
+#endif
+
     if (endsWithSoftBreak)
         return alignment;
 
@@ -379,7 +379,7 @@ ETextAlign RenderBlockFlow::textAlignmentForLine(bool endsWithSoftBreak) const
     case TextAlignLastJustify:
         return JUSTIFY;
     case TextAlignLastAuto:
-        if (style().textJustify() == TextJustifyDistribute)
+        if (textJustify == TextJustifyDistribute)
             return JUSTIFY;
         return TASTART;
     }
@@ -413,8 +413,7 @@ static void updateLogicalWidthForRightAlignedBlock(bool isLeftToRightDirection,
             totalLogicalWidth -= trailingSpaceRun->box()->logicalWidth();
             trailingSpaceRun->box()->setLogicalWidth(0);
         }
-        if (totalLogicalWidth < availableLogicalWidth)
-            logicalLeft += availableLogicalWidth - totalLogicalWidth;
+        logicalLeft += std::max(0.f, availableLogicalWidth - totalLogicalWidth);
         return;
     }
 
@@ -441,8 +440,8 @@ static void updateLogicalWidthForCenterAlignedBlock(bool isLeftToRightDirection,
 
 void RenderBlockFlow::setMarginsForRubyRun(BidiRun* run, RenderRubyRun& renderer, RenderObject* previousObject, const LineInfo& lineInfo)
 {
-    int startOverhang;
-    int endOverhang;
+    float startOverhang;
+    float endOverhang;
     RenderObject* nextObject = 0;
     for (BidiRun* runWithNextObject = run->next(); runWithNextObject; runWithNextObject = runWithNextObject->next()) {
         if (!runWithNextObject->renderer().isOutOfFlowPositioned() && !runWithNextObject->box()->isLineBreak()) {
@@ -455,13 +454,13 @@ void RenderBlockFlow::setMarginsForRubyRun(BidiRun* run, RenderRubyRun& renderer
     setMarginEndForChild(renderer, -endOverhang);
 }
 
-static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* run, RenderText* renderer, float xPos, const LineInfo& lineInfo,
+static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* run, RenderText& renderer, float xPos, const LineInfo& lineInfo,
     GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache, WordMeasurements& wordMeasurements)
 {
-    HashSet<const SimpleFontData*> fallbackFonts;
+    HashSet<const Font*> fallbackFonts;
     GlyphOverflow glyphOverflow;
 
-    const Font& font = lineStyle(*renderer->parent(), lineInfo).font();
+    const FontCascade& font = lineStyle(*renderer.parent(), lineInfo).fontCascade();
     // Always compute glyph overflow if the block's line-box-contain value is "glyphs".
     if (lineBox->fitsToGlyphs()) {
         // If we don't stick out of the root line's font box, then don't bother computing our glyph overflow. This optimization
@@ -477,40 +476,43 @@ static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* ru
     }
     
     LayoutUnit hyphenWidth = 0;
-    if (toInlineTextBox(run->box())->hasHyphen())
+    if (downcast<InlineTextBox>(*run->box()).hasHyphen())
         hyphenWidth = measureHyphenWidth(renderer, font, &fallbackFonts);
 
     float measuredWidth = 0;
 
-    bool kerningIsEnabled = font.typesettingFeatures() & Kerning;
-    bool canUseSimpleFontCodePath = renderer->canUseSimpleFontCodePath();
+    bool kerningIsEnabled = font.enableKerning();
+    bool canUseSimpleFontCodePath = renderer.canUseSimpleFontCodePath();
     
     // Since we don't cache glyph overflows, we need to re-measure the run if
     // the style is linebox-contain: glyph.
-    
     if (!lineBox->fitsToGlyphs() && canUseSimpleFontCodePath) {
-        int lastEndOffset = run->m_start;
+        unsigned lastEndOffset = run->m_start;
+        bool atFirstWordMeasurement = true;
         for (size_t i = 0, size = wordMeasurements.size(); i < size && lastEndOffset < run->m_stop; ++i) {
             WordMeasurement& wordMeasurement = wordMeasurements[i];
             if (wordMeasurement.width <= 0 || wordMeasurement.startOffset == wordMeasurement.endOffset)
                 continue;
-            if (wordMeasurement.renderer != renderer || wordMeasurement.startOffset != lastEndOffset || wordMeasurement.endOffset > run->m_stop)
+            if (wordMeasurement.renderer != &renderer || wordMeasurement.startOffset != lastEndOffset || wordMeasurement.endOffset > run->m_stop)
                 continue;
 
             lastEndOffset = wordMeasurement.endOffset;
             if (kerningIsEnabled && lastEndOffset == run->m_stop) {
                 int wordLength = lastEndOffset - wordMeasurement.startOffset;
                 GlyphOverflow overflow;
-                measuredWidth += renderer->width(wordMeasurement.startOffset, wordLength, xPos + measuredWidth, lineInfo.isFirstLine(),
+                measuredWidth += renderer.width(wordMeasurement.startOffset, wordLength, xPos + measuredWidth, lineInfo.isFirstLine(),
                     &wordMeasurement.fallbackFonts, &overflow);
-                UChar c = renderer->characterAt(wordMeasurement.startOffset);
-                if (i > 0 && wordLength == 1 && (c == ' ' || c == '\t'))
-                    measuredWidth += renderer->style().font().wordSpacing();
+                UChar c = renderer.characterAt(wordMeasurement.startOffset);
+                // renderer.width() omits word-spacing value for leading whitespace, so let's just add it back here.
+                if (!atFirstWordMeasurement && (c == ' ' || c == '\t'))
+                    measuredWidth += renderer.style().fontCascade().wordSpacing();
             } else
                 measuredWidth += wordMeasurement.width;
+            atFirstWordMeasurement = false;
+
             if (!wordMeasurement.fallbackFonts.isEmpty()) {
-                HashSet<const SimpleFontData*>::const_iterator end = wordMeasurement.fallbackFonts.end();
-                for (HashSet<const SimpleFontData*>::const_iterator it = wordMeasurement.fallbackFonts.begin(); it != end; ++it)
+                HashSet<const Font*>::const_iterator end = wordMeasurement.fallbackFonts.end();
+                for (HashSet<const Font*>::const_iterator it = wordMeasurement.fallbackFonts.begin(); it != end; ++it)
                     fallbackFonts.add(*it);
             }
         }
@@ -522,60 +524,108 @@ static inline void setLogicalWidthForTextRun(RootInlineBox* lineBox, BidiRun* ru
     }
 
     if (!measuredWidth)
-        measuredWidth = renderer->width(run->m_start, run->m_stop - run->m_start, xPos, lineInfo.isFirstLine(), &fallbackFonts, &glyphOverflow);
+        measuredWidth = renderer.width(run->m_start, run->m_stop - run->m_start, xPos, lineInfo.isFirstLine(), &fallbackFonts, &glyphOverflow);
 
     run->box()->setLogicalWidth(measuredWidth + hyphenWidth);
     if (!fallbackFonts.isEmpty()) {
         ASSERT(run->box()->behavesLikeText());
-        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(toInlineTextBox(run->box()), std::make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).iterator;
+        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(downcast<InlineTextBox>(run->box()), std::make_pair(Vector<const Font*>(), GlyphOverflow())).iterator;
         ASSERT(it->value.first.isEmpty());
         copyToVector(fallbackFonts, it->value.first);
         run->box()->parent()->clearDescendantsHaveSameLineHeightAndBaseline();
     }
-    if ((glyphOverflow.top || glyphOverflow.bottom || glyphOverflow.left || glyphOverflow.right)) {
+
+    // Include text decoration visual overflow as part of the glyph overflow.
+    if (renderer.style().textDecorationsInEffect() != TextDecorationNone)
+        glyphOverflow.extendTo(visualOverflowForDecorations(run->box()->lineStyle(), downcast<InlineTextBox>(run->box())));
+
+    if (!glyphOverflow.isEmpty()) {
         ASSERT(run->box()->behavesLikeText());
-        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(toInlineTextBox(run->box()), std::make_pair(Vector<const SimpleFontData*>(), GlyphOverflow())).iterator;
+        GlyphOverflowAndFallbackFontsMap::iterator it = textBoxDataMap.add(downcast<InlineTextBox>(run->box()), std::make_pair(Vector<const Font*>(), GlyphOverflow())).iterator;
         it->value.second = glyphOverflow;
         run->box()->clearKnownToHaveNoOverflow();
     }
 }
 
-static inline void computeExpansionForJustifiedText(BidiRun* firstRun, BidiRun* trailingSpaceRun, Vector<unsigned, 16>& expansionOpportunities, unsigned expansionOpportunityCount, float& totalLogicalWidth, float availableLogicalWidth)
+void RenderBlockFlow::updateRubyForJustifiedText(RenderRubyRun& rubyRun, BidiRun& r, const Vector<unsigned, 16>& expansionOpportunities, unsigned& expansionOpportunityCount, float& totalLogicalWidth, float availableLogicalWidth, size_t& i)
+{
+    if (!rubyRun.rubyBase() || !rubyRun.rubyBase()->firstRootBox() || rubyRun.rubyBase()->firstRootBox()->nextRootBox() || !r.renderer().style().collapseWhiteSpace())
+        return;
+
+    auto& rubyBase = *rubyRun.rubyBase();
+    auto& rootBox = *rubyBase.firstRootBox();
+
+    float totalExpansion = 0;
+    unsigned totalOpportunitiesInRun = 0;
+    for (auto* leafChild = rootBox.firstLeafChild(); leafChild; leafChild = leafChild->nextLeafChild()) {
+        if (!leafChild->isInlineTextBox())
+            continue;
+
+        unsigned opportunitiesInRun = expansionOpportunities[i++];
+        ASSERT(opportunitiesInRun <= expansionOpportunityCount);
+        auto expansion = (availableLogicalWidth - totalLogicalWidth) * opportunitiesInRun / expansionOpportunityCount;
+        totalExpansion += expansion;
+        totalOpportunitiesInRun += opportunitiesInRun;
+    }
+
+    ASSERT(!rubyRun.hasOverrideLogicalContentWidth());
+    float newBaseWidth = rubyRun.logicalWidth() + totalExpansion + marginStartForChild(rubyRun) + marginEndForChild(rubyRun);
+    float newRubyRunWidth = rubyRun.logicalWidth() + totalExpansion;
+    rubyBase.setInitialOffset((newRubyRunWidth - newBaseWidth) / 2);
+    rubyRun.setOverrideLogicalContentWidth(newRubyRunWidth);
+    rubyRun.setNeedsLayout(MarkOnlyThis);
+    rootBox.markDirty();
+    if (RenderRubyText* rubyText = rubyRun.rubyText()) {
+        if (RootInlineBox* textRootBox = rubyText->firstRootBox())
+            textRootBox->markDirty();
+    }
+    rubyRun.layoutBlock(true);
+    rubyRun.clearOverrideLogicalContentWidth();
+    r.box()->setExpansion(newRubyRunWidth - r.box()->logicalWidth());
+
+    totalLogicalWidth += totalExpansion;
+    expansionOpportunityCount -= totalOpportunitiesInRun;
+}
+
+void RenderBlockFlow::computeExpansionForJustifiedText(BidiRun* firstRun, BidiRun* trailingSpaceRun, const Vector<unsigned, 16>& expansionOpportunities, unsigned expansionOpportunityCount, float totalLogicalWidth, float availableLogicalWidth)
 {
     if (!expansionOpportunityCount || availableLogicalWidth <= totalLogicalWidth)
         return;
 
     size_t i = 0;
-    for (BidiRun* r = firstRun; r; r = r->next()) {
-#if ENABLE(CSS_SHAPES)
-        // This method is called once per segment, do not move past the current segment.
-        if (r->m_startsSegment)
-            break;
-#endif
-        if (!r->box() || r == trailingSpaceRun)
+    for (BidiRun* run = firstRun; run; run = run->next()) {
+        if (!run->box() || run == trailingSpaceRun)
             continue;
         
-        if (r->renderer().isText()) {
+        if (is<RenderText>(run->renderer())) {
             unsigned opportunitiesInRun = expansionOpportunities[i++];
             
             ASSERT(opportunitiesInRun <= expansionOpportunityCount);
             
             // Only justify text if whitespace is collapsed.
-            if (r->renderer().style().collapseWhiteSpace()) {
-                InlineTextBox* textBox = toInlineTextBox(r->box());
-                int expansion = (availableLogicalWidth - totalLogicalWidth) * opportunitiesInRun / expansionOpportunityCount;
-                textBox->setExpansion(expansion);
+            if (run->renderer().style().collapseWhiteSpace()) {
+                InlineTextBox& textBox = downcast<InlineTextBox>(*run->box());
+                float expansion = (availableLogicalWidth - totalLogicalWidth) * opportunitiesInRun / expansionOpportunityCount;
+                textBox.setExpansion(expansion);
                 totalLogicalWidth += expansion;
             }
             expansionOpportunityCount -= opportunitiesInRun;
-            if (!expansionOpportunityCount)
-                break;
-        }
+        } else if (is<RenderRubyRun>(run->renderer()))
+            updateRubyForJustifiedText(downcast<RenderRubyRun>(run->renderer()), *run, expansionOpportunities, expansionOpportunityCount, totalLogicalWidth, availableLogicalWidth, i);
+
+        if (!expansionOpportunityCount)
+            break;
     }
 }
 
-void RenderBlockFlow::updateLogicalWidthForAlignment(const ETextAlign& textAlign, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, int expansionOpportunityCount)
+void RenderBlockFlow::updateLogicalWidthForAlignment(const ETextAlign& textAlign, const RootInlineBox* rootInlineBox, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, int expansionOpportunityCount)
 {
+    TextDirection direction;
+    if (rootInlineBox && style().unicodeBidi() == Plaintext)
+        direction = rootInlineBox->direction();
+    else
+        direction = style().direction();
+
     // Armed with the total width of the line (without justification),
     // we now examine our text-align property in order to determine where to position the
     // objects horizontally. The total width of the line can be increased if we end up
@@ -604,13 +654,13 @@ void RenderBlockFlow::updateLogicalWidthForAlignment(const ETextAlign& textAlign
         }
         FALLTHROUGH;
     case TASTART:
-        if (style().isLeftToRightDirection())
+        if (direction == LTR)
             updateLogicalWidthForLeftAlignedBlock(style().isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
         else
             updateLogicalWidthForRightAlignedBlock(style().isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
         break;
     case TAEND:
-        if (style().isLeftToRightDirection())
+        if (direction == LTR)
             updateLogicalWidthForRightAlignedBlock(style().isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
         else
             updateLogicalWidthForLeftAlignedBlock(style().isLeftToRightDirection(), trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth);
@@ -618,11 +668,17 @@ void RenderBlockFlow::updateLogicalWidthForAlignment(const ETextAlign& textAlign
     }
 }
 
-static void updateLogicalInlinePositions(RenderBlockFlow& block, float& lineLogicalLeft, float& lineLogicalRight, float& availableLogicalWidth, bool firstLine, IndentTextOrNot shouldIndentText, LayoutUnit boxLogicalHeight)
+static void updateLogicalInlinePositions(RenderBlockFlow& block, float& lineLogicalLeft, float& lineLogicalRight, float& availableLogicalWidth, bool firstLine,
+    IndentTextOrNot shouldIndentText, LayoutUnit boxLogicalHeight, RootInlineBox* rootBox)
 {
     LayoutUnit lineLogicalHeight = block.minLineHeightForReplacedRenderer(firstLine, boxLogicalHeight);
-    lineLogicalLeft = block.pixelSnappedLogicalLeftOffsetForLine(block.logicalHeight(), shouldIndentText == IndentText, lineLogicalHeight);
-    lineLogicalRight = block.pixelSnappedLogicalRightOffsetForLine(block.logicalHeight(), shouldIndentText == IndentText, lineLogicalHeight);
+    if (rootBox->hasAnonymousInlineBlock()) {
+        lineLogicalLeft = block.logicalLeftOffsetForContent(block.logicalHeight());
+        lineLogicalRight = block.logicalRightOffsetForContent(block.logicalHeight());
+    } else {
+        lineLogicalLeft = block.logicalLeftOffsetForLine(block.logicalHeight(), shouldIndentText, lineLogicalHeight);
+        lineLogicalRight = block.logicalRightOffsetForLine(block.logicalHeight(), shouldIndentText, lineLogicalHeight);
+    }
     availableLogicalWidth = lineLogicalRight - lineLogicalLeft;
 }
 
@@ -640,121 +696,295 @@ void RenderBlockFlow::computeInlineDirectionPositionsForLine(RootInlineBox* line
     float lineLogicalLeft;
     float lineLogicalRight;
     float availableLogicalWidth;
-    updateLogicalInlinePositions(*this, lineLogicalLeft, lineLogicalRight, availableLogicalWidth, isFirstLine, shouldIndentText, 0);
+    updateLogicalInlinePositions(*this, lineLogicalLeft, lineLogicalRight, availableLogicalWidth, isFirstLine, shouldIndentText, 0, lineBox);
     bool needsWordSpacing;
-#if ENABLE(CSS_SHAPES)
-    ShapeInsideInfo* shapeInsideInfo = layoutShapeInsideInfo();
-    if (shapeInsideInfo && shapeInsideInfo->hasSegments()) {
-        BidiRun* segmentStart = firstRun;
-        const SegmentList& segments = shapeInsideInfo->segments();
-        float logicalLeft = std::max<float>(roundToInt(segments[0].logicalLeft), lineLogicalLeft);
-        float logicalRight = std::min<float>(floorToInt(segments[0].logicalRight), lineLogicalRight);
-        float startLogicalLeft = logicalLeft;
-        float endLogicalRight = logicalLeft;
-        float minLogicalLeft = logicalLeft;
-        float maxLogicalRight = logicalLeft;
-        lineBox->beginPlacingBoxRangesInInlineDirection(logicalLeft);
-        for (size_t i = 0; i < segments.size(); i++) {
-            if (i) {
-                logicalLeft = std::max<float>(roundToInt(segments[i].logicalLeft), lineLogicalLeft);
-                logicalRight = std::min<float>(floorToInt(segments[i].logicalRight), lineLogicalRight);
-            }
-            availableLogicalWidth = logicalRight - logicalLeft;
-            BidiRun* newSegmentStart = computeInlineDirectionPositionsForSegment(lineBox, lineInfo, textAlign, logicalLeft, availableLogicalWidth, segmentStart, trailingSpaceRun, textBoxDataMap, verticalPositionCache, wordMeasurements);
-            needsWordSpacing = false;
-            endLogicalRight = lineBox->placeBoxRangeInInlineDirection(segmentStart->box(), newSegmentStart ? newSegmentStart->box() : 0, logicalLeft, minLogicalLeft, maxLogicalRight, needsWordSpacing, textBoxDataMap);
-            if (!newSegmentStart || !newSegmentStart->next())
-                break;
-            ASSERT(newSegmentStart->m_startsSegment);
-            // Discard the empty segment start marker bidi runs
-            segmentStart = newSegmentStart->next();
-        }
-        lineBox->endPlacingBoxRangesInInlineDirection(startLogicalLeft, endLogicalRight, minLogicalLeft, maxLogicalRight);
-        return;
-    }
-#endif
 
     if (firstRun && firstRun->renderer().isReplaced()) {
-        RenderBox& renderBox = toRenderBox(firstRun->renderer());
-        updateLogicalInlinePositions(*this, lineLogicalLeft, lineLogicalRight, availableLogicalWidth, isFirstLine, shouldIndentText, renderBox.logicalHeight());
+        RenderBox& renderBox = downcast<RenderBox>(firstRun->renderer());
+        updateLogicalInlinePositions(*this, lineLogicalLeft, lineLogicalRight, availableLogicalWidth, isFirstLine, shouldIndentText, renderBox.logicalHeight(), lineBox);
     }
 
     computeInlineDirectionPositionsForSegment(lineBox, lineInfo, textAlign, lineLogicalLeft, availableLogicalWidth, firstRun, trailingSpaceRun, textBoxDataMap, verticalPositionCache, wordMeasurements);
     // The widths of all runs are now known. We can now place every inline box (and
     // compute accurate widths for the inline flow boxes).
     needsWordSpacing = false;
-    lineBox->placeBoxesInInlineDirection(lineLogicalLeft, needsWordSpacing, textBoxDataMap);
+    lineBox->placeBoxesInInlineDirection(lineLogicalLeft, needsWordSpacing);
+}
+
+static inline ExpansionBehavior expansionBehaviorForInlineTextBox(RenderBlockFlow& block, InlineTextBox& textBox, BidiRun* previousRun, BidiRun* nextRun, ETextAlign textAlign, bool isAfterExpansion)
+{
+    // Tatechuyoko is modeled as the Object Replacement Character (U+FFFC), which can never have expansion opportunities inside nor intrinsically adjacent to it.
+    if (textBox.renderer().style().textCombine() == TextCombineHorizontal)
+        return ForbidLeadingExpansion | ForbidTrailingExpansion;
+
+    ExpansionBehavior result = 0;
+    bool setLeadingExpansion = false;
+    bool setTrailingExpansion = false;
+    if (textAlign == JUSTIFY) {
+        // If the next box is ruby, and we're justifying, and the first box in the ruby base has a leading expansion, and we are a text box, then force a trailing expansion.
+        if (nextRun && is<RenderRubyRun>(nextRun->renderer()) && downcast<RenderRubyRun>(nextRun->renderer()).rubyBase() && nextRun->renderer().style().collapseWhiteSpace()) {
+            auto& rubyBase = *downcast<RenderRubyRun>(nextRun->renderer()).rubyBase();
+            if (rubyBase.firstRootBox() && !rubyBase.firstRootBox()->nextRootBox()) {
+                if (auto* leafChild = rubyBase.firstRootBox()->firstLeafChild()) {
+                    if (is<InlineTextBox>(*leafChild)) {
+                        // FIXME: This leadingExpansionOpportunity doesn't actually work because it doesn't perform the UBA
+                        if (FontCascade::leadingExpansionOpportunity(downcast<RenderText>(leafChild->renderer()).stringView(), leafChild->direction())) {
+                            setTrailingExpansion = true;
+                            result |= ForceTrailingExpansion;
+                        }
+                    }
+                }
+            }
+        }
+        // Same thing, except if we're following a ruby
+        if (previousRun && is<RenderRubyRun>(previousRun->renderer()) && downcast<RenderRubyRun>(previousRun->renderer()).rubyBase() && previousRun->renderer().style().collapseWhiteSpace()) {
+            auto& rubyBase = *downcast<RenderRubyRun>(previousRun->renderer()).rubyBase();
+            if (rubyBase.firstRootBox() && !rubyBase.firstRootBox()->nextRootBox()) {
+                if (auto* leafChild = rubyBase.firstRootBox()->lastLeafChild()) {
+                    if (is<InlineTextBox>(*leafChild)) {
+                        // FIXME: This leadingExpansionOpportunity doesn't actually work because it doesn't perform the UBA
+                        if (FontCascade::trailingExpansionOpportunity(downcast<RenderText>(leafChild->renderer()).stringView(), leafChild->direction())) {
+                            setLeadingExpansion = true;
+                            result |= ForceLeadingExpansion;
+                        }
+                    }
+                }
+            }
+        }
+        // If we're the first box inside a ruby base, forbid a leading expansion, and vice-versa
+        if (is<RenderRubyBase>(block)) {
+            RenderRubyBase& rubyBase = downcast<RenderRubyBase>(block);
+            if (&textBox == rubyBase.firstRootBox()->firstLeafChild()) {
+                setLeadingExpansion = true;
+                result |= ForbidLeadingExpansion;
+            } if (&textBox == rubyBase.firstRootBox()->lastLeafChild()) {
+                setTrailingExpansion = true;
+                result |= ForbidTrailingExpansion;
+            }
+        }
+    }
+    if (!setLeadingExpansion)
+        result |= isAfterExpansion ? ForbidLeadingExpansion : AllowLeadingExpansion;
+    if (!setTrailingExpansion)
+        result |= AllowTrailingExpansion;
+    return result;
+}
+
+static inline void applyExpansionBehavior(InlineTextBox& textBox, ExpansionBehavior expansionBehavior)
+{
+    switch (expansionBehavior & LeadingExpansionMask) {
+    case ForceLeadingExpansion:
+        textBox.setForceLeadingExpansion();
+        break;
+    case ForbidLeadingExpansion:
+        textBox.setCanHaveLeadingExpansion(false);
+        break;
+    case AllowLeadingExpansion:
+        textBox.setCanHaveLeadingExpansion(true);
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        break;
+    }
+    switch (expansionBehavior & TrailingExpansionMask) {
+    case ForceTrailingExpansion:
+        textBox.setForceTrailingExpansion();
+        break;
+    case ForbidTrailingExpansion:
+        textBox.setCanHaveTrailingExpansion(false);
+        break;
+    case AllowTrailingExpansion:
+        textBox.setCanHaveTrailingExpansion(true);
+        break;
+    default:
+        ASSERT_NOT_REACHED();
+        break;
+    }
 }
 
+static bool inlineAncestorHasStartBorderPaddingOrMargin(const RenderBlockFlow& block, const InlineBox& box)
+{
+    bool isLTR = block.style().isLeftToRightDirection();
+    for (auto* currentBox = box.parent(); currentBox; currentBox = currentBox->parent()) {
+        if ((isLTR && currentBox->marginBorderPaddingLogicalLeft() > 0)
+            || (!isLTR && currentBox->marginBorderPaddingLogicalRight() > 0))
+            return true;
+    }
+    return false;
+}
+
+static bool inlineAncestorHasEndBorderPaddingOrMargin(const RenderBlockFlow& block, const InlineBox& box)
+{
+    bool isLTR = block.style().isLeftToRightDirection();
+    for (auto* currentBox = box.parent(); currentBox; currentBox = currentBox->parent()) {
+        if ((isLTR && currentBox->marginBorderPaddingLogicalRight() > 0)
+            || (!isLTR && currentBox->marginBorderPaddingLogicalLeft() > 0))
+            return true;
+    }
+    return false;
+}
+    
+static bool isLastInFlowRun(BidiRun& runToCheck)
+{
+    for (auto* run = runToCheck.next(); run; run = run->next()) {
+        if (!run->box() || run->renderer().isOutOfFlowPositioned() || run->box()->isLineBreak())
+            continue;
+        return false;
+    }
+    return true;
+}
+    
 BidiRun* RenderBlockFlow::computeInlineDirectionPositionsForSegment(RootInlineBox* lineBox, const LineInfo& lineInfo, ETextAlign textAlign, float& logicalLeft, 
     float& availableLogicalWidth, BidiRun* firstRun, BidiRun* trailingSpaceRun, GlyphOverflowAndFallbackFontsMap& textBoxDataMap, VerticalPositionCache& verticalPositionCache,
     WordMeasurements& wordMeasurements)
 {
     bool needsWordSpacing = false;
+    bool canHangPunctuationAtStart = style().hangingPunctuation() & FirstHangingPunctuation;
+    bool canHangPunctuationAtEnd = style().hangingPunctuation() & LastHangingPunctuation;
+    bool isLTR = style().isLeftToRightDirection();
     float totalLogicalWidth = lineBox->getFlowSpacingLogicalWidth();
     unsigned expansionOpportunityCount = 0;
-    bool isAfterExpansion = true;
+    bool isAfterExpansion = is<RenderRubyBase>(*this) ? downcast<RenderRubyBase>(*this).isAfterExpansion() : true;
     Vector<unsigned, 16> expansionOpportunities;
-    RenderObject* previousObject = 0;
-
-    BidiRun* r = firstRun;
-    for (; r; r = r->next()) {
-#if ENABLE(CSS_SHAPES)
-        // Once we have reached the start of the next segment, we have finished
-        // computing the positions for this segment's contents.
-        if (r->m_startsSegment)
-            break;
-#endif
-        if (!r->box() || r->renderer().isOutOfFlowPositioned() || r->box()->isLineBreak())
+
+    BidiRun* run = firstRun;
+    BidiRun* previousRun = nullptr;
+    for (; run; run = run->next()) {
+        auto computeExpansionOpportunities = [&expansionOpportunities, &expansionOpportunityCount, textAlign, &isAfterExpansion] (RenderBlockFlow& block,
+            InlineTextBox& textBox, BidiRun* previousRun, BidiRun* nextRun, const StringView& stringView, TextDirection direction)
+        {
+            if (stringView.isEmpty()) {
+                // Empty runs should still produce an entry in expansionOpportunities list so that the number of items matches the number of runs.
+                expansionOpportunities.append(0);
+                return;
+            }
+            ExpansionBehavior expansionBehavior = expansionBehaviorForInlineTextBox(block, textBox, previousRun, nextRun, textAlign, isAfterExpansion);
+            applyExpansionBehavior(textBox, expansionBehavior);
+            unsigned opportunitiesInRun;
+            std::tie(opportunitiesInRun, isAfterExpansion) = FontCascade::expansionOpportunityCount(stringView, direction, expansionBehavior);
+            expansionOpportunities.append(opportunitiesInRun);
+            expansionOpportunityCount += opportunitiesInRun;
+        };
+        if (!run->box() || run->renderer().isOutOfFlowPositioned() || run->box()->isLineBreak()) {
             continue; // Positioned objects are only participating to figure out their
                       // correct static x position.  They have no effect on the width.
                       // Similarly, line break boxes have no effect on the width.
-        if (r->renderer().isText()) {
-            RenderText& rt = toRenderText(r->renderer());
-            if (textAlign == JUSTIFY && r != trailingSpaceRun) {
-                if (!isAfterExpansion)
-                    toInlineTextBox(r->box())->setCanHaveLeadingExpansion(true);
-                unsigned opportunitiesInRun;
-                if (rt.is8Bit())
-                    opportunitiesInRun = Font::expansionOpportunityCount(rt.characters8() + r->m_start, r->m_stop - r->m_start, r->box()->direction(), isAfterExpansion);
-                else
-                    opportunitiesInRun = Font::expansionOpportunityCount(rt.characters16() + r->m_start, r->m_stop - r->m_start, r->box()->direction(), isAfterExpansion);
-                expansionOpportunities.append(opportunitiesInRun);
-                expansionOpportunityCount += opportunitiesInRun;
+        }
+        if (is<RenderText>(run->renderer())) {
+            auto& renderText = downcast<RenderText>(run->renderer());
+            auto& textBox = downcast<InlineTextBox>(*run->box());
+            if (canHangPunctuationAtStart && lineInfo.isFirstLine() && (isLTR || isLastInFlowRun(*run))
+                && !inlineAncestorHasStartBorderPaddingOrMargin(*this, *run->box())) {
+                float hangStartWidth = renderText.hangablePunctuationStartWidth(run->m_start);
+                availableLogicalWidth += hangStartWidth;
+                if (style().isLeftToRightDirection())
+                    logicalLeft -= hangStartWidth;
+                canHangPunctuationAtStart = false;
             }
-
-            if (int length = rt.textLength()) {
-                if (!r->m_start && needsWordSpacing && isSpaceOrNewline(rt.characterAt(r->m_start)))
-                    totalLogicalWidth += lineStyle(*rt.parent(), lineInfo).font().wordSpacing();
-                needsWordSpacing = !isSpaceOrNewline(rt.characterAt(r->m_stop - 1)) && r->m_stop == length;
+            
+            if (canHangPunctuationAtEnd && lineInfo.isLastLine() && run->m_stop > 0 && (!isLTR || isLastInFlowRun(*run))
+                && !inlineAncestorHasEndBorderPaddingOrMargin(*this, *run->box())) {
+                float hangEndWidth = renderText.hangablePunctuationEndWidth(run->m_stop - 1);
+                availableLogicalWidth += hangEndWidth;
+                if (!style().isLeftToRightDirection())
+                    logicalLeft -= hangEndWidth;
+                canHangPunctuationAtEnd = false;
+            }
+            
+            if (textAlign == JUSTIFY && run != trailingSpaceRun)
+                computeExpansionOpportunities(*this, textBox, previousRun, run->next(), renderText.stringView(run->m_start, run->m_stop), run->box()->direction());
+
+            if (unsigned length = renderText.textLength()) {
+                if (!run->m_start && needsWordSpacing && isSpaceOrNewline(renderText.characterAt(run->m_start)))
+                    totalLogicalWidth += lineStyle(*renderText.parent(), lineInfo).fontCascade().wordSpacing();
+                // run->m_start == run->m_stop should only be true iff the run is a replaced run for bidi: isolate.
+                ASSERT(run->m_stop > 0 || run->m_start == run->m_stop);
+                needsWordSpacing = run->m_stop == length && !isSpaceOrNewline(renderText.characterAt(run->m_stop - 1));
             }
 
-            setLogicalWidthForTextRun(lineBox, r, &rt, totalLogicalWidth, lineInfo, textBoxDataMap, verticalPositionCache, wordMeasurements);
+            setLogicalWidthForTextRun(lineBox, run, renderText, totalLogicalWidth, lineInfo, textBoxDataMap, verticalPositionCache, wordMeasurements);
         } else {
-            isAfterExpansion = false;
-            if (!r->renderer().isRenderInline()) {
-                RenderBox& renderBox = toRenderBox(r->renderer());
-                if (renderBox.isRubyRun())
-                    setMarginsForRubyRun(r, toRenderRubyRun(renderBox), previousObject, lineInfo);
-                r->box()->setLogicalWidth(logicalWidthForChild(renderBox));
+            canHangPunctuationAtStart = false;
+            bool encounteredJustifiedRuby = false;
+            if (is<RenderRubyRun>(run->renderer()) && textAlign == JUSTIFY && run != trailingSpaceRun && downcast<RenderRubyRun>(run->renderer()).rubyBase()) {
+                auto* rubyBase = downcast<RenderRubyRun>(run->renderer()).rubyBase();
+                if (rubyBase->firstRootBox() && !rubyBase->firstRootBox()->nextRootBox() && run->renderer().style().collapseWhiteSpace()) {
+                    rubyBase->setIsAfterExpansion(isAfterExpansion);
+                    for (auto* leafChild = rubyBase->firstRootBox()->firstLeafChild(); leafChild; leafChild = leafChild->nextLeafChild()) {
+                        if (!is<InlineTextBox>(*leafChild))
+                            continue;
+                        encounteredJustifiedRuby = true;
+                        computeExpansionOpportunities(*rubyBase, downcast<InlineTextBox>(*leafChild), nullptr, nullptr,
+                            downcast<RenderText>(leafChild->renderer()).stringView(), leafChild->direction());
+                    }
+                }
+            }
+
+            if (!encounteredJustifiedRuby)
+                isAfterExpansion = false;
+
+            if (!is<RenderInline>(run->renderer())) {
+                auto& renderBox = downcast<RenderBox>(run->renderer());
+                if (is<RenderRubyRun>(renderBox))
+                    setMarginsForRubyRun(run, downcast<RenderRubyRun>(renderBox), previousRun ? &previousRun->renderer() : nullptr, lineInfo);
+                run->box()->setLogicalWidth(logicalWidthForChild(renderBox));
                 totalLogicalWidth += marginStartForChild(renderBox) + marginEndForChild(renderBox);
             }
         }
 
-        totalLogicalWidth += r->box()->logicalWidth();
-        previousObject = &r->renderer();
+        totalLogicalWidth += run->box()->logicalWidth();
+        previousRun = run;
     }
 
     if (isAfterExpansion && !expansionOpportunities.isEmpty()) {
-        expansionOpportunities.last()--;
-        expansionOpportunityCount--;
+        // FIXME: see <webkit.org/b/139393#c11>
+        int lastValidExpansionOpportunitiesIndex = expansionOpportunities.size() - 1;
+        while (lastValidExpansionOpportunitiesIndex >= 0 && !expansionOpportunities.at(lastValidExpansionOpportunitiesIndex))
+            --lastValidExpansionOpportunitiesIndex;
+        if (lastValidExpansionOpportunitiesIndex >= 0) {
+            ASSERT(expansionOpportunities.at(lastValidExpansionOpportunitiesIndex));
+            expansionOpportunities.at(lastValidExpansionOpportunitiesIndex)--;
+            expansionOpportunityCount--;
+        }
     }
 
-    updateLogicalWidthForAlignment(textAlign, trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth, expansionOpportunityCount);
+    if (is<RenderRubyBase>(*this) && !expansionOpportunityCount)
+        textAlign = CENTER;
+
+    updateLogicalWidthForAlignment(textAlign, lineBox, trailingSpaceRun, logicalLeft, totalLogicalWidth, availableLogicalWidth, expansionOpportunityCount);
 
     computeExpansionForJustifiedText(firstRun, trailingSpaceRun, expansionOpportunities, expansionOpportunityCount, totalLogicalWidth, availableLogicalWidth);
 
-    return r;
+    return run;
+}
+
+void RenderBlockFlow::removeInlineBox(BidiRun& run, const RootInlineBox& rootLineBox) const
+{
+    auto* inlineBox = run.box();
+#if !ASSERT_DISABLED
+    auto* inlineParent = inlineBox->parent();
+    while (inlineParent && inlineParent != &rootLineBox) {
+        ASSERT(!inlineParent->isDirty());
+        inlineParent = inlineParent->parent();
+    }
+    ASSERT(!rootLineBox.isDirty());
+#endif
+    auto* parent = inlineBox->parent();
+    inlineBox->removeFromParent();
+
+    auto& renderer = run.renderer();
+    if (is<RenderText>(renderer))
+        downcast<RenderText>(renderer).removeTextBox(downcast<InlineTextBox>(*inlineBox));
+    delete inlineBox;
+    run.setBox(nullptr);
+    // removeFromParent() unnecessarily dirties the ancestor subtree.
+    auto* ancestor = parent;
+    while (ancestor) {
+        ancestor->markDirty(false);
+        if (ancestor == &rootLineBox)
+            break;
+        ancestor = ancestor->parent();
+    }
 }
 
 void RenderBlockFlow::computeBlockDirectionPositionsForLine(RootInlineBox* lineBox, BidiRun* firstRun, GlyphOverflowAndFallbackFontsMap& textBoxDataMap,
@@ -763,30 +993,33 @@ void RenderBlockFlow::computeBlockDirectionPositionsForLine(RootInlineBox* lineB
     setLogicalHeight(lineBox->alignBoxesInBlockDirection(logicalHeight(), textBoxDataMap, verticalPositionCache));
 
     // Now make sure we place replaced render objects correctly.
-    for (BidiRun* r = firstRun; r; r = r->next()) {
-        ASSERT(r->box());
-        if (!r->box())
+    for (auto* run = firstRun; run; run = run->next()) {
+        ASSERT(run->box());
+        if (!run->box())
             continue; // Skip runs with no line boxes.
 
-        InlineBox& box = *r->box();
-
         // Align positioned boxes with the top of the line box.  This is
         // a reasonable approximation of an appropriate y position.
-        if (r->renderer().isOutOfFlowPositioned())
-            box.setLogicalTop(logicalHeight());
+        auto& renderer = run->renderer();
+        if (renderer.isOutOfFlowPositioned())
+            run->box()->setLogicalTop(logicalHeight());
 
         // Position is used to properly position both replaced elements and
         // to update the static normal flow x/y of positioned elements.
-        if (r->renderer().isText())
-            toRenderText(r->renderer()).positionLineBox(toInlineTextBox(box));
-        else if (r->renderer().isBox())
-            toRenderBox(r->renderer()).positionLineBox(toInlineElementBox(box));
-        else if (r->renderer().isLineBreak())
-            toRenderLineBreak(r->renderer()).replaceInlineBoxWrapper(toInlineElementBox(box));
-    }
-    // Positioned objects and zero-length text nodes destroy their boxes in
-    // position(), which unnecessarily dirties the line.
-    lineBox->markDirty(false);
+        bool inlineBoxIsRedundant = false;
+        if (is<RenderText>(renderer)) {
+            auto& inlineTextBox = downcast<InlineTextBox>(*run->box());
+            downcast<RenderText>(renderer).positionLineBox(inlineTextBox);
+            inlineBoxIsRedundant = !inlineTextBox.len();
+        } else if (is<RenderBox>(renderer)) {
+            downcast<RenderBox>(renderer).positionLineBox(downcast<InlineElementBox>(*run->box()));
+            inlineBoxIsRedundant = renderer.isOutOfFlowPositioned();
+        } else if (is<RenderLineBreak>(renderer))
+            downcast<RenderLineBreak>(renderer).replaceInlineBoxWrapper(downcast<InlineElementBox>(*run->box()));
+        // Check if we need to keep this box on the line at all.
+        if (inlineBoxIsRedundant)
+            removeInlineBox(*run, *lineBox);
+    }
 }
 
 static inline bool isCollapsibleSpace(UChar character, const RenderText& renderer)
@@ -801,9 +1034,9 @@ static inline bool isCollapsibleSpace(UChar character, const RenderText& rendere
 }
 
 template <typename CharacterType>
-static inline int findFirstTrailingSpace(const RenderText& lastText, const CharacterType* characters, int start, int stop)
+static inline unsigned findFirstTrailingSpace(const RenderText& lastText, const CharacterType* characters, unsigned start, unsigned stop)
 {
-    int firstSpace = stop;
+    unsigned firstSpace = stop;
     while (firstSpace > start) {
         UChar current = characters[firstSpace - 1];
         if (!isCollapsibleSpace(current, lastText))
@@ -819,22 +1052,22 @@ inline BidiRun* RenderBlockFlow::handleTrailingSpaces(BidiRunList<BidiRun>& bidi
     if (!bidiRuns.runCount()
         || !bidiRuns.logicallyLastRun()->renderer().style().breakOnlyAfterWhiteSpace()
         || !bidiRuns.logicallyLastRun()->renderer().style().autoWrap())
-        return 0;
+        return nullptr;
 
     BidiRun* trailingSpaceRun = bidiRuns.logicallyLastRun();
     const RenderObject& lastObject = trailingSpaceRun->renderer();
-    if (!lastObject.isText())
-        return 0;
+    if (!is<RenderText>(lastObject))
+        return nullptr;
 
-    const RenderText& lastText = toRenderText(lastObject);
-    int firstSpace;
+    const RenderText& lastText = downcast<RenderText>(lastObject);
+    unsigned firstSpace;
     if (lastText.is8Bit())
         firstSpace = findFirstTrailingSpace(lastText, lastText.characters8(), trailingSpaceRun->start(), trailingSpaceRun->stop());
     else
         firstSpace = findFirstTrailingSpace(lastText, lastText.characters16(), trailingSpaceRun->start(), trailingSpaceRun->stop());
 
     if (firstSpace == trailingSpaceRun->stop())
-        return 0;
+        return nullptr;
 
     TextDirection direction = style().direction();
     bool shouldReorder = trailingSpaceRun != (direction == LTR ? bidiRuns.lastRun() : bidiRuns.firstRun());
@@ -843,13 +1076,13 @@ inline BidiRun* RenderBlockFlow::handleTrailingSpaces(BidiRunList<BidiRun>& bidi
         while (BidiContext* parent = baseContext->parent())
             baseContext = parent;
 
-        BidiRun* newTrailingRun = new BidiRun(firstSpace, trailingSpaceRun->m_stop, trailingSpaceRun->renderer(), baseContext, U_OTHER_NEUTRAL);
+        std::unique_ptr<BidiRun> newTrailingRun = std::make_unique<BidiRun>(firstSpace, trailingSpaceRun->m_stop, trailingSpaceRun->renderer(), baseContext, U_OTHER_NEUTRAL);
         trailingSpaceRun->m_stop = firstSpace;
+        trailingSpaceRun = newTrailingRun.get();
         if (direction == LTR)
-            bidiRuns.addRun(newTrailingRun);
+            bidiRuns.appendRun(WTFMove(newTrailingRun));
         else
-            bidiRuns.prependRun(newTrailingRun);
-        trailingSpaceRun = newTrailingRun;
+            bidiRuns.prependRun(WTFMove(newTrailingRun));
         return trailingSpaceRun;
     }
     if (!shouldReorder)
@@ -865,22 +1098,32 @@ inline BidiRun* RenderBlockFlow::handleTrailingSpaces(BidiRunList<BidiRun>& bidi
     return trailingSpaceRun;
 }
 
-void RenderBlockFlow::appendFloatingObjectToLastLine(FloatingObject* floatingObject)
+void RenderBlockFlow::appendFloatingObjectToLastLine(FloatingObject& floatingObject)
 {
-    ASSERT(!floatingObject->originatingLine());
-    floatingObject->setOriginatingLine(lastRootBox());
-    lastRootBox()->appendFloat(floatingObject->renderer());
+    ASSERT_WITH_SECURITY_IMPLICATION(!floatingObject.originatingLine());
+    floatingObject.setOriginatingLine(lastRootBox());
+    lastRootBox()->appendFloat(floatingObject.renderer());
 }
 
-static inline void setUpResolverToResumeInIsolate(InlineBidiResolver& resolver, RenderObject* root, RenderObject* startObject)
+static inline void notifyResolverToResumeInIsolate(InlineBidiResolver& resolver, RenderObject* root, RenderObject* startObject)
 {
     if (root != startObject) {
         RenderObject* parent = startObject->parent();
-        setUpResolverToResumeInIsolate(resolver, root, parent);
+        notifyResolverToResumeInIsolate(resolver, root, parent);
         notifyObserverEnteredObject(&resolver, startObject);
     }
 }
 
+static inline void setUpResolverToResumeInIsolate(InlineBidiResolver& resolver, InlineBidiResolver& topResolver, BidiRun& isolatedRun, RenderObject* root, RenderObject* startObject)
+{
+    // Set up m_whitespaceCollapsingState
+    resolver.whitespaceCollapsingState() = topResolver.whitespaceCollapsingState();
+    resolver.whitespaceCollapsingState().setCurrentTransition(topResolver.whitespaceCollapsingTransitionForIsolatedRun(isolatedRun));
+
+    // Set up m_nestedIsolateCount
+    notifyResolverToResumeInIsolate(resolver, root, startObject);
+}
+
 // FIXME: BidiResolver should have this logic.
 static inline void constructBidiRunsForSegment(InlineBidiResolver& topResolver, BidiRunList<BidiRun>& bidiRuns, const InlineIterator& endOfRuns, VisualDirectionOverride override, bool previousLineBrokeCleanly)
 {
@@ -893,36 +1136,37 @@ static inline void constructBidiRunsForSegment(InlineBidiResolver& topResolver,
 
     while (!topResolver.isolatedRuns().isEmpty()) {
         // It does not matter which order we resolve the runs as long as we resolve them all.
-        BidiRun* isolatedRun = topResolver.isolatedRuns().last();
+        auto isolatedRun = WTFMove(topResolver.isolatedRuns().last());
         topResolver.isolatedRuns().removeLast();
+        currentRoot = &isolatedRun.root;
 
-        RenderObject& startObject = isolatedRun->renderer();
+        RenderObject& startObject = isolatedRun.object;
 
         // Only inlines make sense with unicode-bidi: isolate (blocks are already isolated).
         // FIXME: Because enterIsolate is not passed a RenderObject, we have to crawl up the
         // tree to see which parent inline is the isolate. We could change enterIsolate
         // to take a RenderObject and do this logic there, but that would be a layering
         // violation for BidiResolver (which knows nothing about RenderObject).
-        RenderInline* isolatedInline = toRenderInline(highestContainingIsolateWithinRoot(startObject, currentRoot));
+        RenderInline* isolatedInline = downcast<RenderInline>(highestContainingIsolateWithinRoot(startObject, currentRoot));
         ASSERT(isolatedInline);
 
         InlineBidiResolver isolatedResolver;
         EUnicodeBidi unicodeBidi = isolatedInline->style().unicodeBidi();
         TextDirection direction;
         if (unicodeBidi == Plaintext)
-            determineDirectionality(direction, InlineIterator(isolatedInline, &isolatedRun->renderer(), 0));
+            determineDirectionality(direction, InlineIterator(isolatedInline, &isolatedRun.object, 0));
         else {
             ASSERT(unicodeBidi == Isolate || unicodeBidi == IsolateOverride);
             direction = isolatedInline->style().direction();
         }
         isolatedResolver.setStatus(BidiStatus(direction, isOverride(unicodeBidi)));
 
-        setUpResolverToResumeInIsolate(isolatedResolver, isolatedInline, &startObject);
+        setUpResolverToResumeInIsolate(isolatedResolver, topResolver, isolatedRun.runToReplace, isolatedInline, &startObject);
 
         // The starting position is the beginning of the first run within the isolate that was identified
         // during the earlier call to createBidiRunsForLine. This can be but is not necessarily the
         // first run within the isolate.
-        InlineIterator iter = InlineIterator(isolatedInline, &startObject, isolatedRun->m_start);
+        InlineIterator iter = InlineIterator(isolatedInline, &startObject, isolatedRun.position);
         isolatedResolver.setPositionIgnoringNestedIsolates(iter);
 
         // We stop at the next end of line; we may re-enter this isolate in the next call to constructBidiRuns().
@@ -934,74 +1178,36 @@ static inline void constructBidiRunsForSegment(InlineBidiResolver& topResolver,
         // itself to be turned into an InlineBox. We can't remove it here without potentially losing track of
         // the logically last run.
         if (isolatedResolver.runs().runCount())
-            bidiRuns.replaceRunWithRuns(isolatedRun, isolatedResolver.runs());
+            bidiRuns.replaceRunWithRuns(&isolatedRun.runToReplace, isolatedResolver.runs());
 
         // If we encountered any nested isolate runs, just move them
         // to the top resolver's list for later processing.
-        if (!isolatedResolver.isolatedRuns().isEmpty()) {
-            topResolver.isolatedRuns().appendVector(isolatedResolver.isolatedRuns());
-            isolatedResolver.isolatedRuns().clear();
-            currentRoot = isolatedInline;
-        }
-    }
-}
-
-static inline void constructBidiRunsForLine(const RenderBlockFlow* block, InlineBidiResolver& topResolver, BidiRunList<BidiRun>& bidiRuns, const InlineIterator& endOfLine, VisualDirectionOverride override, bool previousLineBrokeCleanly)
-{
-#if !ENABLE(CSS_SHAPES)
-    UNUSED_PARAM(block);
-    constructBidiRunsForSegment(topResolver, bidiRuns, endOfLine, override, previousLineBrokeCleanly);
-#else
-    ShapeInsideInfo* shapeInsideInfo = block->layoutShapeInsideInfo();
-    if (!shapeInsideInfo || !shapeInsideInfo->hasSegments()) {
-        constructBidiRunsForSegment(topResolver, bidiRuns, endOfLine, override, previousLineBrokeCleanly);
-        return;
-    }
-
-    const SegmentRangeList& segmentRanges = shapeInsideInfo->segmentRanges();
-    ASSERT(segmentRanges.size());
-
-    for (size_t i = 0; i < segmentRanges.size(); i++) {
-        LineSegmentIterator iterator = segmentRanges[i].start;
-        InlineIterator segmentStart(iterator.root, iterator.object, iterator.offset);
-        iterator = segmentRanges[i].end;
-        InlineIterator segmentEnd(iterator.root, iterator.object, iterator.offset);
-        if (i) {
-            ASSERT(segmentStart.renderer());
-            BidiRun* segmentMarker = createRun(segmentStart.offset(), segmentStart.offset(), segmentStart.renderer(), topResolver);
-            segmentMarker->m_startsSegment = true;
-            bidiRuns.addRun(segmentMarker);
-            // Do not collapse midpoints between segments
-            topResolver.midpointState().setBetweenMidpoints(false);
+        while (!isolatedResolver.isolatedRuns().isEmpty()) {
+            auto runWithContext = WTFMove(isolatedResolver.isolatedRuns().last());
+            isolatedResolver.isolatedRuns().removeLast();
+            topResolver.setWhitespaceCollapsingTransitionForIsolatedRun(runWithContext.runToReplace, isolatedResolver.whitespaceCollapsingTransitionForIsolatedRun(runWithContext.runToReplace));
+            topResolver.isolatedRuns().append(WTFMove(runWithContext));
         }
-        if (segmentStart == segmentEnd)
-            continue;
-        topResolver.setPosition(segmentStart, numberOfIsolateAncestors(segmentStart));
-        constructBidiRunsForSegment(topResolver, bidiRuns, segmentEnd, override, previousLineBrokeCleanly);
     }
-#endif
 }
 
 // This function constructs line boxes for all of the text runs in the resolver and computes their position.
-RootInlineBox* RenderBlockFlow::createLineBoxesFromBidiRuns(BidiRunList<BidiRun>& bidiRuns, const InlineIterator& end, LineInfo& lineInfo, VerticalPositionCache& verticalPositionCache, BidiRun* trailingSpaceRun, WordMeasurements& wordMeasurements)
+RootInlineBox* RenderBlockFlow::createLineBoxesFromBidiRuns(unsigned bidiLevel, BidiRunList<BidiRun>& bidiRuns, const InlineIterator& end, LineInfo& lineInfo, VerticalPositionCache& verticalPositionCache, BidiRun* trailingSpaceRun, WordMeasurements& wordMeasurements)
 {
     if (!bidiRuns.runCount())
-        return 0;
+        return nullptr;
 
     // FIXME: Why is this only done when we had runs?
     lineInfo.setLastLine(!end.renderer());
 
     RootInlineBox* lineBox = constructLine(bidiRuns, lineInfo);
     if (!lineBox)
-        return 0;
+        return nullptr;
 
+    lineBox->setBidiLevel(bidiLevel);
     lineBox->setEndsWithBreak(lineInfo.previousLineBrokeCleanly());
     
-#if ENABLE(SVG)
-    bool isSVGRootInlineBox = lineBox->isSVGRootInlineBox();
-#else
-    bool isSVGRootInlineBox = false;
-#endif
+    bool isSVGRootInlineBox = is<SVGRootInlineBox>(*lineBox);
     
     GlyphOverflowAndFallbackFontsMap textBoxDataMap;
     
@@ -1012,7 +1218,6 @@ RootInlineBox* RenderBlockFlow::createLineBoxesFromBidiRuns(BidiRunList<BidiRun>
     // Now position our text runs vertically.
     computeBlockDirectionPositionsForLine(lineBox, bidiRuns.firstRun(), textBoxDataMap, verticalPositionCache);
     
-#if ENABLE(SVG)
     // SVG text layout code computes vertical & horizontal positions on its own.
     // Note that we still need to execute computeVerticalPositionsForLine() as
     // it calls InlineTextBox::positionLineBox(), which tracks whether the box
@@ -1020,18 +1225,12 @@ RootInlineBox* RenderBlockFlow::createLineBoxesFromBidiRuns(BidiRunList<BidiRun>
     // text selection in RTL boxes would not work as expected.
     if (isSVGRootInlineBox) {
         ASSERT_WITH_SECURITY_IMPLICATION(isSVGText());
-        toSVGRootInlineBox(lineBox)->computePerCharacterLayoutInformation();
+        downcast<SVGRootInlineBox>(*lineBox).computePerCharacterLayoutInformation();
     }
-#endif
     
     // Compute our overflow now.
     lineBox->computeOverflow(lineBox->lineTop(), lineBox->lineBottom(), textBoxDataMap);
     
-#if PLATFORM(MAC)
-    // Highlight acts as an overflow inflation.
-    if (style().highlight() != nullAtom)
-        lineBox->addHighlightOverflow();
-#endif
     return lineBox;
 }
 
@@ -1048,11 +1247,28 @@ static void deleteLineRange(LineLayoutState& layoutState, RootInlineBox* startLi
     }
 }
 
+static void repaintDirtyFloats(LineLayoutState::FloatList& floats)
+{
+    // Floats that did not have layout did not repaint when we laid them out. They would have
+    // painted by now if they had moved, but if they stayed at (0, 0), they still need to be
+    // painted.
+    for (auto& floatBox : floats) {
+        if (floatBox->everHadLayout())
+            continue;
+        auto& box = floatBox->renderer();
+        if (!box.x() && !box.y() && box.checkForRepaintDuringLayout())
+            box.repaint();
+    }
+}
+
 void RenderBlockFlow::layoutRunsAndFloats(LineLayoutState& layoutState, bool hasInlineChild)
 {
     // We want to skip ahead to the first dirty line
     InlineBidiResolver resolver;
     RootInlineBox* startLine = determineStartPosition(layoutState, resolver);
+    
+    if (startLine)
+        marginCollapseLinesFromStart(layoutState, startLine);
 
     unsigned consecutiveHyphenatedLines = 0;
     if (startLine) {
@@ -1065,17 +1281,17 @@ void RenderBlockFlow::layoutRunsAndFloats(LineLayoutState& layoutState, bool has
     // determineStartPosition first will break fast/repaint/line-flow-with-floats-9.html.
     if (layoutState.isFullLayout() && hasInlineChild && !selfNeedsLayout()) {
         setNeedsLayout(MarkOnlyThis); // Mark as needing a full layout to force us to repaint.
-        if (!view().doingFullRepaint() && hasLayer()) {
+        if (!view().doingFullRepaint() && hasSelfPaintingLayer() && layer()->hasComputedRepaintRect()) {
             // Because we waited until we were already inside layout to discover
             // that the block really needed a full layout, we missed our chance to repaint the layer
             // before layout started.  Luckily the layer has cached the repaint rect for its original
             // position and size, and so we can use that to make a repaint happen now.
-            repaintUsingContainer(containerForRepaint(), pixelSnappedIntRect(layer()->repaintRect()));
+            repaintUsingContainer(containerForRepaint(), layer()->repaintRect());
         }
     }
 
     if (containsFloats())
-        layoutState.setLastFloat(m_floatingObjects->set().last().get());
+        layoutState.floatList().setLastFloat(m_floatingObjects->set().last().get());
 
     // We also find the first clean line and extract these lines.  We will add them back
     // if we determine that we're able to synchronize after handling all our dirty lines.
@@ -1101,24 +1317,14 @@ void RenderBlockFlow::layoutRunsAndFloats(LineLayoutState& layoutState, bool has
             if (lastObject->isBR()) {
                 EClear clear = lastObject->style().clear();
                 if (clear != CNONE)
-                    newLine(clear);
+                    clearFloats(clear);
             }
         }
     }
 
     layoutRunsAndFloatsInRange(layoutState, resolver, cleanLineStart, cleanLineBidiStatus, consecutiveHyphenatedLines);
     linkToEndLineIfNeeded(layoutState);
-    repaintDirtyFloats(layoutState.floats());
-}
-
-RenderTextInfo::RenderTextInfo()
-    : m_text(0)
-    , m_font(0)
-{
-}
-
-RenderTextInfo::~RenderTextInfo()
-{
+    repaintDirtyFloats(layoutState.floatList());
 }
 
 // Before restarting the layout loop with a new logicalHeight, remove all floats that were added and reset the resolver.
@@ -1130,175 +1336,11 @@ inline const InlineIterator& RenderBlockFlow::restartLayoutRunsAndFloatsInRange(
     return oldEnd;
 }
 
-#if ENABLE(CSS_SHAPES)
-static inline void pushShapeContentOverflowBelowTheContentBox(RenderBlockFlow* block, ShapeInsideInfo* shapeInsideInfo, LayoutUnit lineTop, LayoutUnit lineHeight)
-{
-    ASSERT(shapeInsideInfo);
-
-    LayoutUnit logicalLineBottom = lineTop + lineHeight;
-    LayoutUnit shapeLogicalBottom = shapeInsideInfo->shapeLogicalBottom();
-    LayoutUnit shapeContainingBlockLogicalHeight = shapeInsideInfo->shapeContainingBlockLogicalHeight();
-
-    bool isOverflowPositionedAlready = (shapeContainingBlockLogicalHeight - shapeInsideInfo->owner().borderAndPaddingAfter() + lineHeight) <= lineTop;
-
-    // If the last line overlaps with the shape, we don't need the segments anymore
-    if (lineTop < shapeLogicalBottom && shapeLogicalBottom < logicalLineBottom)
-        shapeInsideInfo->clearSegments();
-
-    if (logicalLineBottom <= shapeLogicalBottom || !shapeContainingBlockLogicalHeight || isOverflowPositionedAlready)
-        return;
-
-    LayoutUnit newLogicalHeight = block->logicalHeight() + (shapeContainingBlockLogicalHeight - (lineTop + shapeInsideInfo->owner().borderAndPaddingAfter()));
-    block->setLogicalHeight(newLogicalHeight);
-}
-
-void RenderBlockFlow::updateShapeAndSegmentsForCurrentLine(ShapeInsideInfo*& shapeInsideInfo, const LayoutSize& logicalOffsetFromShapeContainer, LineLayoutState& layoutState)
-{
-    if (layoutState.flowThread())
-        return updateShapeAndSegmentsForCurrentLineInFlowThread(shapeInsideInfo, layoutState);
-
-    if (!shapeInsideInfo)
-        return;
-
-    LayoutUnit lineTop = logicalHeight() + logicalOffsetFromShapeContainer.height();
-    LayoutUnit lineLeft = logicalOffsetFromShapeContainer.width();
-    LayoutUnit lineHeight = this->lineHeight(layoutState.lineInfo().isFirstLine(), isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
-
-    // FIXME: Bug 95361: It is possible for a line to grow beyond lineHeight, in which case these segments may be incorrect.
-    shapeInsideInfo->updateSegmentsForLine(LayoutSize(lineLeft, lineTop), lineHeight);
-
-    pushShapeContentOverflowBelowTheContentBox(this, shapeInsideInfo, lineTop, lineHeight);
-}
-
-void RenderBlockFlow::updateShapeAndSegmentsForCurrentLineInFlowThread(ShapeInsideInfo*& shapeInsideInfo, LineLayoutState& layoutState)
-{
-    ASSERT(layoutState.flowThread());
-
-    RenderRegion* currentRegion = regionAtBlockOffset(logicalHeight());
-    if (!currentRegion || !currentRegion->logicalHeight())
-        return;
-
-    shapeInsideInfo = currentRegion->shapeInsideInfo();
-
-    RenderRegion* nextRegion = 0;
-    if (!currentRegion->isLastRegion()) {
-        RenderRegionList regionList = layoutState.flowThread()->renderRegionList();
-        auto it = regionList.find(currentRegion);
-        nextRegion = *(++it);
-    }
-
-    // We only want to deal regions with shapes, so we check if the next region has a shape
-    if (!shapeInsideInfo && nextRegion && !nextRegion->shapeInsideInfo())
-        return;
-
-    LayoutUnit lineHeight = this->lineHeight(layoutState.lineInfo().isFirstLine(), isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes);
-    LayoutUnit logicalLineTopInFlowThread = logicalHeight() + offsetFromLogicalTopOfFirstPage();
-    LayoutUnit logicalLineBottomInFlowThread = logicalLineTopInFlowThread + lineHeight;
-    LayoutUnit logicalRegionTopInFlowThread = currentRegion->logicalTopForFlowThreadContent();
-    LayoutUnit logicalRegionBottomInFlowThread = logicalRegionTopInFlowThread + currentRegion->logicalHeight() - currentRegion->borderAndPaddingBefore() - currentRegion->borderAndPaddingAfter();
-
-    LayoutUnit shapeBottomInFlowThread = LayoutUnit::max();
-    if (shapeInsideInfo)
-        shapeBottomInFlowThread = shapeInsideInfo->shapeLogicalBottom() + currentRegion->logicalTopForFlowThreadContent();
-
-    bool lineOverLapsWithShapeBottom = shapeBottomInFlowThread < logicalLineBottomInFlowThread;
-    bool lineTopAdjustedIntoNextRegion = layoutState.adjustedLogicalLineTop() >= currentRegion->logicalHeight();
-    bool lineOverLapsWithRegionBottom = logicalLineBottomInFlowThread > logicalRegionBottomInFlowThread || lineTopAdjustedIntoNextRegion;
-    bool overFlowsToNextRegion = nextRegion && (lineOverLapsWithShapeBottom || lineOverLapsWithRegionBottom);
-
-    // If the line is between two shapes/regions we position the line to the top of the next shape/region
-    if (overFlowsToNextRegion) {
-        ASSERT(currentRegion != nextRegion);
-        LayoutUnit deltaToNextRegion = logicalRegionBottomInFlowThread - logicalLineTopInFlowThread;
-        setLogicalHeight(logicalHeight() + deltaToNextRegion);
-
-        currentRegion = nextRegion;
-        shapeInsideInfo = currentRegion->shapeInsideInfo();
-
-        logicalLineTopInFlowThread = logicalHeight() + offsetFromLogicalTopOfFirstPage();
-        logicalLineBottomInFlowThread = logicalLineTopInFlowThread + lineHeight;
-        logicalRegionTopInFlowThread = currentRegion->logicalTopForFlowThreadContent();
-        logicalRegionBottomInFlowThread = logicalRegionTopInFlowThread + currentRegion->logicalHeight() - currentRegion->borderAndPaddingBefore() - currentRegion->borderAndPaddingAfter();
-
-        if (lineTopAdjustedIntoNextRegion)
-            layoutState.setAdjustedLogicalLineTop(0);
-    }
-
-    if (!shapeInsideInfo)
-        return;
-
-    bool isFirstLineInRegion = logicalLineBottomInFlowThread <= (logicalRegionTopInFlowThread + lineHeight);
-    bool isFirstLineAdjusted = (logicalLineTopInFlowThread - logicalRegionTopInFlowThread) < (layoutState.adjustedLogicalLineTop() - currentRegion->borderAndPaddingBefore());
-    // We position the first line to the top of the shape in the region or to the previously adjusted position in the shape
-    if (isFirstLineInRegion || isFirstLineAdjusted) {
-        LayoutUnit shapeTopOffset = layoutState.adjustedLogicalLineTop();
-
-        if (!shapeTopOffset && (shapeInsideInfo->shapeLogicalTop() > 0))
-            shapeTopOffset = shapeInsideInfo->shapeLogicalTop();
-
-        LayoutUnit shapePositionInFlowThread = currentRegion->logicalTopForFlowThreadContent() + shapeTopOffset;
-        LayoutUnit shapeTopLineTopDelta = shapePositionInFlowThread - logicalLineTopInFlowThread - currentRegion->borderAndPaddingBefore();
-
-        setLogicalHeight(logicalHeight() + shapeTopLineTopDelta);
-        logicalLineTopInFlowThread += shapeTopLineTopDelta;
-        layoutState.setAdjustedLogicalLineTop(0);
-    }
-
-    LayoutUnit lineTop = logicalLineTopInFlowThread - currentRegion->logicalTopForFlowThreadContent() + currentRegion->borderAndPaddingBefore();
-
-    // FIXME: 118571 - Shape inside on a region does not yet take into account its padding for nested flow blocks
-    shapeInsideInfo->updateSegmentsForLine(LayoutSize(0, lineTop), lineHeight);
-
-    if (currentRegion->isLastRegion())
-        pushShapeContentOverflowBelowTheContentBox(this, shapeInsideInfo, lineTop, lineHeight);
-}
-
-static inline LayoutUnit adjustLogicalLineTop(ShapeInsideInfo* shapeInsideInfo, InlineIterator start, InlineIterator end, const WordMeasurements& wordMeasurements)
-{
-    if (!shapeInsideInfo || end != start)
-        return 0;
-
-    float minWidth = firstPositiveWidth(wordMeasurements);
-    ASSERT(minWidth || wordMeasurements.isEmpty());
-    if (minWidth > 0 && shapeInsideInfo->adjustLogicalLineTop(minWidth))
-        return shapeInsideInfo->logicalLineTop();
-
-    return shapeInsideInfo->shapeLogicalBottom();
-}
-
-bool RenderBlockFlow::adjustLogicalLineTopAndLogicalHeightIfNeeded(ShapeInsideInfo* shapeInsideInfo, LayoutUnit absoluteLogicalTop, LineLayoutState& layoutState, InlineBidiResolver& resolver, FloatingObject* lastFloatFromPreviousLine, InlineIterator& end, WordMeasurements& wordMeasurements)
-{
-    LayoutUnit adjustedLogicalLineTop = adjustLogicalLineTop(shapeInsideInfo, resolver.position(), end, wordMeasurements);
-
-    if (shapeInsideInfo && containsFloats()) {
-        lastFloatFromPreviousLine = m_floatingObjects->set().last().get();
-        if (!wordMeasurements.size()) {
-            LayoutUnit floatLogicalTopOffset = shapeInsideInfo->computeFirstFitPositionForFloat(logicalSizeForFloat(lastFloatFromPreviousLine));
-            if (logicalHeight() < floatLogicalTopOffset)
-                adjustedLogicalLineTop = floatLogicalTopOffset;
-        }
-    }
-
-    if (!adjustedLogicalLineTop)
-        return false;
-
-    LayoutUnit newLogicalHeight = adjustedLogicalLineTop - absoluteLogicalTop;
-
-    if (layoutState.flowThread()) {
-        layoutState.setAdjustedLogicalLineTop(adjustedLogicalLineTop);
-        newLogicalHeight = logicalHeight();
-    }
-
-    end = restartLayoutRunsAndFloatsInRange(logicalHeight(), newLogicalHeight, lastFloatFromPreviousLine, resolver, end);
-    return true;
-}
-#endif
-
 void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, InlineBidiResolver& resolver, const InlineIterator& cleanLineStart, const BidiStatus& cleanLineBidiStatus, unsigned consecutiveHyphenatedLines)
 {
     const RenderStyle& styleToUse = style();
     bool paginated = view().layoutState() && view().layoutState()->isPaginated();
-    LineMidpointState& lineMidpointState = resolver.midpointState();
+    LineWhitespaceCollapsingState& lineWhitespaceCollapsingState = resolver.whitespaceCollapsingState();
     InlineIterator end = resolver.position();
     bool checkForEndLineMatch = layoutState.endLine();
     RenderTextInfo renderTextInfo;
@@ -1306,65 +1348,40 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
 
     LineBreaker lineBreaker(*this);
 
-#if ENABLE(CSS_SHAPES)
-    LayoutSize logicalOffsetFromShapeContainer;
-    ShapeInsideInfo* shapeInsideInfo = layoutShapeInsideInfo();
-    if (shapeInsideInfo) {
-        ASSERT(&shapeInsideInfo->owner() == this || allowsShapeInsideInfoSharing());
-        if (shapeInsideInfo != this->shapeInsideInfo()) {
-            // FIXME Bug 100284: If subsequent LayoutStates are pushed, we will have to add
-            // their offsets from the original shape-inside container.
-            logicalOffsetFromShapeContainer = logicalOffsetFromShapeAncestorContainer(&shapeInsideInfo->owner());
-        }
-        // Begin layout at the logical top of our shape inside.
-        if (logicalHeight() + logicalOffsetFromShapeContainer.height() < shapeInsideInfo->shapeLogicalTop()) {
-            LayoutUnit logicalHeight = shapeInsideInfo->shapeLogicalTop() - logicalOffsetFromShapeContainer.height();
-            if (layoutState.flowThread())
-                logicalHeight -= shapeInsideInfo->owner().borderAndPaddingBefore();
-            setLogicalHeight(logicalHeight);
-        }
-    }
-#endif
-
     while (!end.atEnd()) {
         // FIXME: Is this check necessary before the first iteration or can it be moved to the end?
         if (checkForEndLineMatch) {
             layoutState.setEndLineMatched(matchedEndLine(layoutState, resolver, cleanLineStart, cleanLineBidiStatus));
             if (layoutState.endLineMatched()) {
                 resolver.setPosition(InlineIterator(resolver.position().root(), 0, 0), 0);
+                layoutState.marginInfo().clearMargin();
                 break;
             }
         }
 
-        lineMidpointState.reset();
+        lineWhitespaceCollapsingState.reset();
 
         layoutState.lineInfo().setEmpty(true);
         layoutState.lineInfo().resetRunsFromLeadingWhitespace();
 
         const InlineIterator oldEnd = end;
         bool isNewUBAParagraph = layoutState.lineInfo().previousLineBrokeCleanly();
-        FloatingObject* lastFloatFromPreviousLine = (containsFloats()) ? m_floatingObjects->set().last().get() : 0;
+        FloatingObject* lastFloatFromPreviousLine = (containsFloats()) ? m_floatingObjects->set().last().get() : nullptr;
 
-#if ENABLE(CSS_SHAPES)
-        updateShapeAndSegmentsForCurrentLine(shapeInsideInfo, logicalOffsetFromShapeContainer, layoutState);
-#endif
         WordMeasurements wordMeasurements;
-        end = lineBreaker.nextLineBreak(resolver, layoutState.lineInfo(), renderTextInfo, lastFloatFromPreviousLine, consecutiveHyphenatedLines, wordMeasurements);
-        renderTextInfo.m_lineBreakIterator.resetPriorContext();
+        end = lineBreaker.nextLineBreak(resolver, layoutState.lineInfo(), layoutState, renderTextInfo, lastFloatFromPreviousLine, consecutiveHyphenatedLines, wordMeasurements);
+        cachePriorCharactersIfNeeded(renderTextInfo.lineBreakIterator);
+        renderTextInfo.lineBreakIterator.resetPriorContext();
         if (resolver.position().atEnd()) {
             // FIXME: We shouldn't be creating any runs in nextLineBreak to begin with!
             // Once BidiRunList is separated from BidiResolver this will not be needed.
-            resolver.runs().deleteRuns();
+            resolver.runs().clear();
             resolver.markCurrentRunEmpty(); // FIXME: This can probably be replaced by an ASSERT (or just removed).
             layoutState.setCheckForFloatsFromLastLine(true);
             resolver.setPosition(InlineIterator(resolver.position().root(), 0, 0), 0);
             break;
         }
 
-#if ENABLE(CSS_SHAPES)
-        if (adjustLogicalLineTopAndLogicalHeightIfNeeded(shapeInsideInfo, logicalOffsetFromShapeContainer.height(), layoutState, resolver, lastFloatFromPreviousLine, end, wordMeasurements))
-            continue;
-#endif
         ASSERT(end != resolver.position());
 
         // This is a short-cut for empty lines.
@@ -1381,10 +1398,10 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
             }
             // FIXME: This ownership is reversed. We should own the BidiRunList and pass it to createBidiRunsForLine.
             BidiRunList<BidiRun>& bidiRuns = resolver.runs();
-            constructBidiRunsForLine(this, resolver, bidiRuns, end, override, layoutState.lineInfo().previousLineBrokeCleanly());
+            constructBidiRunsForSegment(resolver, bidiRuns, end, override, layoutState.lineInfo().previousLineBrokeCleanly());
             ASSERT(resolver.position() == end);
 
-            BidiRun* trailingSpaceRun = !layoutState.lineInfo().previousLineBrokeCleanly() ? handleTrailingSpaces(bidiRuns, resolver.context()) : 0;
+            BidiRun* trailingSpaceRun = !layoutState.lineInfo().previousLineBrokeCleanly() ? handleTrailingSpaces(bidiRuns, resolver.context()) : nullptr;
 
             if (bidiRuns.runCount() && lineBreaker.lineWasHyphenated()) {
                 bidiRuns.logicallyLastRun()->m_hasHyphen = true;
@@ -1397,33 +1414,63 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
             // inline flow boxes.
 
             LayoutUnit oldLogicalHeight = logicalHeight();
-            RootInlineBox* lineBox = createLineBoxesFromBidiRuns(bidiRuns, end, layoutState.lineInfo(), verticalPositionCache, trailingSpaceRun, wordMeasurements);
+            RootInlineBox* lineBox = createLineBoxesFromBidiRuns(resolver.status().context->level(), bidiRuns, end, layoutState.lineInfo(), verticalPositionCache, trailingSpaceRun, wordMeasurements);
 
-            bidiRuns.deleteRuns();
+            bidiRuns.clear();
             resolver.markCurrentRunEmpty(); // FIXME: This can probably be replaced by an ASSERT (or just removed).
 
             if (lineBox) {
                 lineBox->setLineBreakInfo(end.renderer(), end.offset(), resolver.status());
                 if (layoutState.usesRepaintBounds())
                     layoutState.updateRepaintRangeFromBox(lineBox);
+                
+                LayoutUnit adjustment = 0;
+                bool overflowsRegion = false;
+                
+                // If our previous line was an anonymous block and we are not an anonymous block,
+                // simulate a margin collapse now so that we get the proper
+                // increased height. We also have to simulate a margin collapse to propagate margins
+                // through to the top of our block.
+                if (!lineBox->hasAnonymousInlineBlock()) {
+                    RootInlineBox* prevRoot = lineBox->prevRootBox();
+                    if (prevRoot && prevRoot->hasAnonymousInlineBlock()) {
+                        LayoutUnit currentLogicalHeight = logicalHeight();
+                        setLogicalHeight(oldLogicalHeight);
+                        collapseMarginsWithChildInfo(nullptr, nullptr, layoutState.marginInfo());
+                        adjustment = logicalHeight() - oldLogicalHeight;
+                        setLogicalHeight(currentLogicalHeight);
+                    }
+                    layoutState.marginInfo().setAtBeforeSideOfBlock(false);
+                }
 
+                if (paginated)
+                    adjustLinePositionForPagination(lineBox, adjustment, overflowsRegion, layoutState.flowThread());
+                if (adjustment) {
+                    IndentTextOrNot shouldIndentText = layoutState.lineInfo().isFirstLine() ? IndentText : DoNotIndentText;
+                    LayoutUnit oldLineWidth = availableLogicalWidthForLine(oldLogicalHeight, shouldIndentText);
+                    lineBox->adjustBlockDirectionPosition(adjustment);
+                    if (layoutState.usesRepaintBounds())
+                        layoutState.updateRepaintRangeFromBox(lineBox);
+
+                    if (availableLogicalWidthForLine(oldLogicalHeight + adjustment, shouldIndentText) != oldLineWidth) {
+                        // We have to delete this line, remove all floats that got added, and let line layout re-run.
+                        lineBox->deleteLine();
+                        end = restartLayoutRunsAndFloatsInRange(oldLogicalHeight, oldLogicalHeight + adjustment, lastFloatFromPreviousLine, resolver, oldEnd);
+                        continue;
+                    }
+
+                    setLogicalHeight(lineBox->lineBottomWithLeading());
+                }
+                    
                 if (paginated) {
-                    LayoutUnit adjustment = 0;
-                    adjustLinePositionForPagination(lineBox, adjustment, layoutState.flowThread());
-                    if (adjustment) {
-                        LayoutUnit oldLineWidth = availableLogicalWidthForLine(oldLogicalHeight, layoutState.lineInfo().isFirstLine());
-                        lineBox->adjustBlockDirectionPosition(adjustment);
-                        if (layoutState.usesRepaintBounds())
-                            layoutState.updateRepaintRangeFromBox(lineBox);
-
-                        if (availableLogicalWidthForLine(oldLogicalHeight + adjustment, layoutState.lineInfo().isFirstLine()) != oldLineWidth) {
-                            // We have to delete this line, remove all floats that got added, and let line layout re-run.
-                            lineBox->deleteLine();
-                            end = restartLayoutRunsAndFloatsInRange(oldLogicalHeight, oldLogicalHeight + adjustment, lastFloatFromPreviousLine, resolver, oldEnd);
-                            continue;
+                    if (RenderFlowThread* flowThread = flowThreadContainingBlock()) {
+                        if (flowThread->isRenderNamedFlowThread() && overflowsRegion && hasNextPage(lineBox->lineTop())) {
+                            // Limit the height of this block to the end of the current region because
+                            // it is also fragmented into the next region.
+                            LayoutUnit remainingLogicalHeight = pageRemainingLogicalHeightForOffset(logicalTop(), ExcludePageBoundary);
+                            if (logicalHeight() > remainingLogicalHeight)
+                                setLogicalHeight(remainingLogicalHeight);
                         }
-
-                        setLogicalHeight(lineBox->lineBottomWithLeading());
                     }
 
                     if (layoutState.flowThread())
@@ -1433,36 +1480,35 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
         }
 
         for (size_t i = 0; i < lineBreaker.positionedObjects().size(); ++i)
-            setStaticPositions(*this, *lineBreaker.positionedObjects()[i]);
+            setStaticPositions(*this, *lineBreaker.positionedObjects()[i], DoNotIndentText);
 
         if (!layoutState.lineInfo().isEmpty()) {
             layoutState.lineInfo().setFirstLine(false);
-            newLine(lineBreaker.clear());
+            clearFloats(lineBreaker.clear());
         }
 
         if (m_floatingObjects && lastRootBox()) {
             const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
             auto it = floatingObjectSet.begin();
             auto end = floatingObjectSet.end();
-            if (layoutState.lastFloat()) {
-                auto lastFloatIterator = floatingObjectSet.find<FloatingObject&, FloatingObjectHashTranslator>(*layoutState.lastFloat());
+            if (auto* lastFloat = layoutState.floatList().lastFloat()) {
+                auto lastFloatIterator = floatingObjectSet.find<FloatingObject&, FloatingObjectHashTranslator>(*lastFloat);
                 ASSERT(lastFloatIterator != end);
                 ++lastFloatIterator;
                 it = lastFloatIterator;
             }
             for (; it != end; ++it) {
-                FloatingObject* f = it->get();
-                appendFloatingObjectToLastLine(f);
-                ASSERT(&f->renderer() == &layoutState.floats()[layoutState.floatIndex()].object);
+                auto& floatingObject = *it;
+                appendFloatingObjectToLastLine(*floatingObject);
                 // If a float's geometry has changed, give up on syncing with clean lines.
-                if (layoutState.floats()[layoutState.floatIndex()].rect != f->frameRect())
+                auto* floatWithRect = layoutState.floatList().floatWithRect(floatingObject->renderer());
+                if (!floatWithRect || floatWithRect->rect() != floatingObject->frameRect())
                     checkForEndLineMatch = false;
-                layoutState.setFloatIndex(layoutState.floatIndex() + 1);
             }
-            layoutState.setLastFloat(!floatingObjectSet.isEmpty() ? floatingObjectSet.last().get() : nullptr);
+            layoutState.floatList().setLastFloat(!floatingObjectSet.isEmpty() ? floatingObjectSet.last().get() : nullptr);
         }
 
-        lineMidpointState.reset();
+        lineWhitespaceCollapsingState.reset();
         resolver.setPosition(end, numberOfIsolateAncestors(end));
     }
 
@@ -1525,22 +1571,44 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState, I
             markLinesDirtyInBlockRange(lastRootBox()->lineBottomWithLeading(), lineBox->lineBottomWithLeading(), lineBox);
         }
     }
-
     clearDidBreakAtLineToAvoidWidow();
 }
 
+void RenderBlockFlow::reattachCleanLineFloats(RootInlineBox& cleanLine, LayoutUnit delta, bool isFirstCleanLine)
+{
+    auto* cleanLineFloats = cleanLine.floatsPtr();
+    if (!cleanLineFloats)
+        return;
+
+    for (auto* floatingBox : *cleanLineFloats) {
+        auto* floatingObject = insertFloatingObject(*floatingBox);
+        if (isFirstCleanLine && floatingObject->originatingLine()) {
+            // Float box does not belong to this line anymore.
+            ASSERT_WITH_SECURITY_IMPLICATION(cleanLine.prevRootBox() == floatingObject->originatingLine());
+            cleanLine.removeFloat(*floatingBox);
+            continue;
+        }
+        ASSERT_WITH_SECURITY_IMPLICATION(!floatingObject->originatingLine());
+        floatingObject->setOriginatingLine(&cleanLine);
+        setLogicalHeight(logicalTopForChild(*floatingBox) - marginBeforeForChild(*floatingBox) + delta);
+        positionNewFloats();
+    }
+}
+
 void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
 {
-    if (layoutState.endLine()) {
+    auto* firstCleanLine = layoutState.endLine();
+    if (firstCleanLine) {
         if (layoutState.endLineMatched()) {
             bool paginated = view().layoutState() && view().layoutState()->isPaginated();
             // Attach all the remaining lines, and then adjust their y-positions as needed.
             LayoutUnit delta = logicalHeight() - layoutState.endLineLogicalTop();
-            for (RootInlineBox* line = layoutState.endLine(); line; line = line->nextRootBox()) {
+            for (auto* line = firstCleanLine; line; line = line->nextRootBox()) {
                 line->attachLine();
                 if (paginated) {
                     delta -= line->paginationStrut();
-                    adjustLinePositionForPagination(line, delta, layoutState.flowThread());
+                    bool overflowsRegion;
+                    adjustLinePositionForPagination(line, delta, overflowsRegion, layoutState.flowThread());
                 }
                 if (delta) {
                     layoutState.updateRepaintRangeFromBox(line, delta);
@@ -1548,16 +1616,7 @@ void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
                 }
                 if (layoutState.flowThread())
                     updateRegionForLine(line);
-                if (Vector<RenderBox*>* cleanLineFloats = line->floatsPtr()) {
-                    for (auto it = cleanLineFloats->begin(), end = cleanLineFloats->end(); it != end; ++it) {
-                        RenderBox* floatingBox = *it;
-                        FloatingObject* floatingObject = insertFloatingObject(*floatingBox);
-                        ASSERT(!floatingObject->originatingLine());
-                        floatingObject->setOriginatingLine(line);
-                        setLogicalHeight(logicalTopForChild(*floatingBox) - marginBeforeForChild(*floatingBox) + delta);
-                        positionNewFloats();
-                    }
-                }
+                reattachCleanLineFloats(*line, delta, line == firstCleanLine);
             }
             setLogicalHeight(lastRootBox()->lineBottomWithLeading());
         } else {
@@ -1575,7 +1634,7 @@ void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
             LayoutUnit bottomLayoutOverflow = lastRootBox()->logicalBottomLayoutOverflow();
             auto newLineBox = std::make_unique<TrailingFloatsRootInlineBox>(*this);
             auto trailingFloatsLineBox = newLineBox.get();
-            m_lineBoxes.appendLineBox(std::move(newLineBox));
+            m_lineBoxes.appendLineBox(WTFMove(newLineBox));
             trailingFloatsLineBox->setConstructed();
             GlyphOverflowAndFallbackFontsMap textBoxDataMap;
             VerticalPositionCache verticalPositionCache;
@@ -1593,30 +1652,15 @@ void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)
         const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
         auto it = floatingObjectSet.begin();
         auto end = floatingObjectSet.end();
-        if (layoutState.lastFloat()) {
-            auto lastFloatIterator = floatingObjectSet.find<FloatingObject&, FloatingObjectHashTranslator>(*layoutState.lastFloat());
+        if (auto* lastFloat = layoutState.floatList().lastFloat()) {
+            auto lastFloatIterator = floatingObjectSet.find<FloatingObject&, FloatingObjectHashTranslator>(*lastFloat);
             ASSERT(lastFloatIterator != end);
             ++lastFloatIterator;
             it = lastFloatIterator;
         }
         for (; it != end; ++it)
-            appendFloatingObjectToLastLine(it->get());
-        layoutState.setLastFloat(!floatingObjectSet.isEmpty() ? floatingObjectSet.last().get() : nullptr);
-    }
-}
-
-void RenderBlockFlow::repaintDirtyFloats(Vector<FloatWithRect>& floats)
-{
-    size_t floatCount = floats.size();
-    // Floats that did not have layout did not repaint when we laid them out. They would have
-    // painted by now if they had moved, but if they stayed at (0, 0), they still need to be
-    // painted.
-    for (size_t i = 0; i < floatCount; ++i) {
-        if (!floats[i].everHadLayout) {
-            RenderBox& box = floats[i].object;
-            if (!box.x() && !box.y() && box.checkForRepaintDuringLayout())
-                box.repaint();
-        }
+            appendFloatingObjectToLastLine(**it);
+        layoutState.floatList().setLastFloat(!floatingObjectSet.isEmpty() ? floatingObjectSet.last().get() : nullptr);
     }
 }
 
@@ -1636,7 +1680,7 @@ void RenderBlockFlow::layoutLineBoxes(bool relayoutChildren, LayoutUnit& repaint
     // Figure out if we should clear out our line boxes.
     // FIXME: Handle resize eventually!
     bool isFullLayout = !firstRootBox() || selfNeedsLayout() || relayoutChildren || clearLinesForPagination;
-    LineLayoutState layoutState(isFullLayout, repaintLogicalTop, repaintLogicalBottom, flowThread);
+    LineLayoutState layoutState(*this, isFullLayout, repaintLogicalTop, repaintLogicalBottom, flowThread);
 
     if (isFullLayout)
         lineBoxes().deleteLineBoxes();
@@ -1669,7 +1713,7 @@ void RenderBlockFlow::layoutLineBoxes(bool relayoutChildren, LayoutUnit& repaint
                 hasInlineChild = true;
 
             if (o.isReplaced() || o.isFloating() || o.isOutOfFlowPositioned()) {
-                RenderBox& box = toRenderBox(o);
+                RenderBox& box = downcast<RenderBox>(o);
 
                 if (relayoutChildren || box.hasRelativeDimensions())
                     box.setChildNeedsLayout(MarkOnlyThis);
@@ -1681,18 +1725,20 @@ void RenderBlockFlow::layoutLineBoxes(bool relayoutChildren, LayoutUnit& repaint
                 if (box.isOutOfFlowPositioned())
                     box.containingBlock()->insertPositionedObject(box);
                 else if (box.isFloating())
-                    layoutState.floats().append(FloatWithRect(box));
+                    layoutState.floatList().append(FloatWithRect::create(box));
                 else if (isFullLayout || box.needsLayout()) {
                     // Replaced element.
                     box.dirtyLineBoxes(isFullLayout);
-                    if (isFullLayout)
-                        replacedChildren.append(&box);
-                    else
-                        box.layoutIfNeeded();
+                    if (!o.isAnonymousInlineBlock()) {
+                        if (isFullLayout)
+                            replacedChildren.append(&box);
+                        else
+                            box.layoutIfNeeded();
+                    }
                 }
-            } else if (o.isTextOrLineBreak() || (o.isRenderInline() && !walker.atEndOfInline())) {
-                if (o.isRenderInline())
-                    toRenderInline(o).updateAlwaysCreateLineBoxes(layoutState.isFullLayout());
+            } else if (o.isTextOrLineBreak() || (is<RenderInline>(o) && !walker.atEndOfInline())) {
+                if (is<RenderInline>(o))
+                    downcast<RenderInline>(o).updateAlwaysCreateLineBoxes(layoutState.isFullLayout());
                 if (layoutState.isFullLayout() || o.selfNeedsLayout())
                     dirtyLineBoxesForRenderer(o, layoutState.isFullLayout());
                 o.clearNeedsLayout();
@@ -1714,9 +1760,17 @@ void RenderBlockFlow::layoutLineBoxes(bool relayoutChildren, LayoutUnit& repaint
         else
             lastLineAnnotationsAdjustment = lastRootBox()->computeOverAnnotationAdjustment(lowestAllowedPosition);
     }
-
-    // Now add in the bottom border/padding.
-    setLogicalHeight(logicalHeight() + lastLineAnnotationsAdjustment + borderAndPaddingAfter() + scrollbarLogicalHeight());
+    
+    // Now do the handling of the bottom of the block, adding in our bottom border/padding and
+    // determining the correct collapsed bottom margin information. This collapse is only necessary
+    // if our last child was an anonymous inline block that might need to propagate margin information out to
+    // us.
+    LayoutUnit beforeEdge = borderAndPaddingBefore();
+    LayoutUnit afterEdge = borderAndPaddingAfter() + scrollbarLogicalHeight() + lastLineAnnotationsAdjustment;
+    if (lastRootBox() && lastRootBox()->hasAnonymousInlineBlock())
+        handleAfterSideOfBlock(beforeEdge, afterEdge, layoutState.marginInfo());
+    else
+        setLogicalHeight(logicalHeight() + afterEdge);
 
     if (!firstRootBox() && hasLineIfEmpty())
         setLogicalHeight(logicalHeight() + lineHeight(true, isHorizontalWritingMode() ? HorizontalLine : VerticalLine, PositionOfInteriorLineBoxes));
@@ -1727,146 +1781,146 @@ void RenderBlockFlow::layoutLineBoxes(bool relayoutChildren, LayoutUnit& repaint
         checkLinesForTextOverflow();
 }
 
-void RenderBlockFlow::checkFloatsInCleanLine(RootInlineBox* line, Vector<FloatWithRect>& floats, size_t& floatIndex, bool& encounteredNewFloat, bool& dirtiedByFloat)
+void RenderBlockFlow::checkFloatInCleanLine(RootInlineBox& cleanLine, RenderBox& floatBoxOnCleanLine, FloatWithRect& matchingFloatWithRect,
+    bool& encounteredNewFloat, bool& dirtiedByFloat)
 {
-    Vector<RenderBox*>* cleanLineFloats = line->floatsPtr();
-    if (!cleanLineFloats)
-        return;
-    
-    if (!floats.size()) {
+    ASSERT_WITH_SECURITY_IMPLICATION(!floatBoxOnCleanLine.style().deletionHasBegun());
+    if (&matchingFloatWithRect.renderer() != &floatBoxOnCleanLine) {
         encounteredNewFloat = true;
         return;
     }
+    floatBoxOnCleanLine.layoutIfNeeded();
+    LayoutRect originalFloatRect = matchingFloatWithRect.rect();
+    LayoutSize newSize(
+        floatBoxOnCleanLine.width() + floatBoxOnCleanLine.horizontalMarginExtent(),
+        floatBoxOnCleanLine.height() + floatBoxOnCleanLine.verticalMarginExtent());
+    
+    // We have to reset the cap-height alignment done by the first-letter floats when initial-letter is set, so just always treat first-letter floats as dirty.
+    if (originalFloatRect.size() == newSize && (floatBoxOnCleanLine.style().styleType() != FIRST_LETTER || !floatBoxOnCleanLine.style().initialLetterDrop()))
+        return;
 
-    for (auto it = cleanLineFloats->begin(), end = cleanLineFloats->end(); it != end; ++it) {
-        RenderBox* floatingBox = *it;
-        floatingBox->layoutIfNeeded();
-        LayoutSize newSize(floatingBox->width() + floatingBox->marginWidth(), floatingBox->height() + floatingBox->marginHeight());
-        ASSERT_WITH_SECURITY_IMPLICATION(floatIndex < floats.size());
-        if (&floats[floatIndex].object != floatingBox) {
-            encounteredNewFloat = true;
-            return;
-        }
-
-        if (floats[floatIndex].rect.size() != newSize) {
-            LayoutUnit floatTop = isHorizontalWritingMode() ? floats[floatIndex].rect.y() : floats[floatIndex].rect.x();
-            LayoutUnit floatHeight = isHorizontalWritingMode() ? std::max(floats[floatIndex].rect.height(), newSize.height()) : std::max(floats[floatIndex].rect.width(), newSize.width());
-            floatHeight = std::min(floatHeight, LayoutUnit::max() - floatTop);
-            line->markDirty();
-            markLinesDirtyInBlockRange(line->lineBottomWithLeading(), floatTop + floatHeight, line);
-            floats[floatIndex].rect.setSize(newSize);
-            dirtiedByFloat = true;
-        }
-        floatIndex++;
-    }
+    LayoutUnit floatTop = isHorizontalWritingMode() ? originalFloatRect.y() : originalFloatRect.x();
+    LayoutUnit floatHeight = isHorizontalWritingMode() ? std::max(originalFloatRect.height(), newSize.height())
+        : std::max(originalFloatRect.width(), newSize.width());
+    floatHeight = std::min(floatHeight, LayoutUnit::max() - floatTop);
+    cleanLine.markDirty();
+    markLinesDirtyInBlockRange(cleanLine.lineBottomWithLeading(), floatTop + floatHeight, &cleanLine);
+    LayoutRect newFloatRect = originalFloatRect;
+    newFloatRect.setSize(newSize);
+    matchingFloatWithRect.adjustRect(newFloatRect);
+    dirtiedByFloat = true;
 }
 
 RootInlineBox* RenderBlockFlow::determineStartPosition(LineLayoutState& layoutState, InlineBidiResolver& resolver)
 {
-    RootInlineBox* curr = 0;
-    RootInlineBox* last = 0;
+    RootInlineBox* currentLine = nullptr;
+    RootInlineBox* lastLine = nullptr;
 
     // FIXME: This entire float-checking block needs to be broken into a new function.
+    auto& floats = layoutState.floatList();
     bool dirtiedByFloat = false;
     if (!layoutState.isFullLayout()) {
         // Paginate all of the clean lines.
         bool paginated = view().layoutState() && view().layoutState()->isPaginated();
         LayoutUnit paginationDelta = 0;
-        size_t floatIndex = 0;
-        for (curr = firstRootBox(); curr && !curr->isDirty(); curr = curr->nextRootBox()) {
+        auto floatsIterator = floats.begin();
+        auto end = floats.end();
+        for (currentLine = firstRootBox(); currentLine && !currentLine->isDirty(); currentLine = currentLine->nextRootBox()) {
             if (paginated) {
-                if (lineWidthForPaginatedLineChanged(curr, 0, layoutState.flowThread())) {
-                    curr->markDirty();
+                if (lineWidthForPaginatedLineChanged(currentLine, 0, layoutState.flowThread())) {
+                    currentLine->markDirty();
                     break;
                 }
-                paginationDelta -= curr->paginationStrut();
-                adjustLinePositionForPagination(curr, paginationDelta, layoutState.flowThread());
+                paginationDelta -= currentLine->paginationStrut();
+                bool overflowsRegion;
+                adjustLinePositionForPagination(currentLine, paginationDelta, overflowsRegion, layoutState.flowThread());
                 if (paginationDelta) {
-                    if (containsFloats() || !layoutState.floats().isEmpty()) {
+                    if (containsFloats() || !floats.isEmpty()) {
                         // FIXME: Do better eventually.  For now if we ever shift because of pagination and floats are present just go to a full layout.
                         layoutState.markForFullLayout();
                         break;
                     }
 
-                    layoutState.updateRepaintRangeFromBox(curr, paginationDelta);
-                    curr->adjustBlockDirectionPosition(paginationDelta);
+                    layoutState.updateRepaintRangeFromBox(currentLine, paginationDelta);
+                    currentLine->adjustBlockDirectionPosition(paginationDelta);
                 }
                 if (layoutState.flowThread())
-                    updateRegionForLine(curr);
+                    updateRegionForLine(currentLine);
             }
 
-            // If a new float has been inserted before this line or before its last known float, just do a full layout.
-            bool encounteredNewFloat = false;
-            checkFloatsInCleanLine(curr, layoutState.floats(), floatIndex, encounteredNewFloat, dirtiedByFloat);
-            if (encounteredNewFloat)
-                layoutState.markForFullLayout();
-
-            if (dirtiedByFloat || layoutState.isFullLayout())
-                break;
+            if (auto* cleanLineFloats = currentLine->floatsPtr()) {
+                // If a new float has been inserted before this line or before its last known float, just do a full layout.
+                bool encounteredNewFloat = false;
+                for (auto* floatBoxOnCleanLine : *cleanLineFloats) {
+                    ASSERT(floatsIterator != end);
+                    checkFloatInCleanLine(*currentLine, *floatBoxOnCleanLine, *floatsIterator, encounteredNewFloat, dirtiedByFloat);
+                    ++floatsIterator;
+                    if (floatsIterator == end || encounteredNewFloat) {
+                        layoutState.markForFullLayout();
+                        break;
+                    }
+                }
+                if (dirtiedByFloat || encounteredNewFloat)
+                    break;
+            }
         }
         // Check if a new float has been inserted after the last known float.
-        if (!curr && floatIndex < layoutState.floats().size())
+        if (!currentLine && floatsIterator != end)
             layoutState.markForFullLayout();
     }
 
     if (layoutState.isFullLayout()) {
         m_lineBoxes.deleteLineBoxTree();
-        curr = 0;
-
+        currentLine = nullptr;
         ASSERT(!firstRootBox() && !lastRootBox());
     } else {
-        if (curr) {
+        if (currentLine) {
             // We have a dirty line.
-            if (RootInlineBox* prevRootBox = curr->prevRootBox()) {
+            if (RootInlineBox* prevRootBox = currentLine->prevRootBox()) {
                 // We have a previous line.
-                if (!dirtiedByFloat && (!prevRootBox->endsWithBreak() || !prevRootBox->lineBreakObj() || (prevRootBox->lineBreakObj()->isText() && prevRootBox->lineBreakPos() >= toRenderText(prevRootBox->lineBreakObj())->textLength())))
+                if (!dirtiedByFloat && !currentLine->hasAnonymousInlineBlock() && (!prevRootBox->endsWithBreak()
+                    || !prevRootBox->lineBreakObj()
+                    || (is<RenderText>(*prevRootBox->lineBreakObj())
+                    && prevRootBox->lineBreakPos() >= downcast<RenderText>(*prevRootBox->lineBreakObj()).textLength()))) {
                     // The previous line didn't break cleanly or broke at a newline
                     // that has been deleted, so treat it as dirty too.
-                    curr = prevRootBox;
+                    currentLine = prevRootBox;
+                }
             }
-        } else {
-            // No dirty lines were found.
-            // If the last line didn't break cleanly, treat it as dirty.
-            if (lastRootBox() && !lastRootBox()->endsWithBreak())
-                curr = lastRootBox();
         }
-
         // If we have no dirty lines, then last is just the last root box.
-        last = curr ? curr->prevRootBox() : lastRootBox();
+        lastLine = currentLine ? currentLine->prevRootBox() : lastRootBox();
     }
 
-    unsigned numCleanFloats = 0;
-    if (!layoutState.floats().isEmpty()) {
+    if (!floats.isEmpty()) {
         LayoutUnit savedLogicalHeight = logicalHeight();
         // Restore floats from clean lines.
         RootInlineBox* line = firstRootBox();
-        while (line != curr) {
+        while (line != currentLine) {
             if (Vector<RenderBox*>* cleanLineFloats = line->floatsPtr()) {
                 for (auto it = cleanLineFloats->begin(), end = cleanLineFloats->end(); it != end; ++it) {
-                    RenderBox* floatingBox = *it;
-                    FloatingObject* floatingObject = insertFloatingObject(*floatingBox);
-                    ASSERT(!floatingObject->originatingLine());
+                    auto* floatingBox = *it;
+                    auto* floatingObject = insertFloatingObject(*floatingBox);
+                    ASSERT_WITH_SECURITY_IMPLICATION(!floatingObject->originatingLine());
                     floatingObject->setOriginatingLine(line);
                     setLogicalHeight(logicalTopForChild(*floatingBox) - marginBeforeForChild(*floatingBox));
                     positionNewFloats();
-                    ASSERT(&layoutState.floats()[numCleanFloats].object == floatingBox);
-                    numCleanFloats++;
+                    floats.setLastCleanFloat(*floatingBox);
                 }
             }
             line = line->nextRootBox();
         }
         setLogicalHeight(savedLogicalHeight);
     }
-    layoutState.setFloatIndex(numCleanFloats);
 
-    layoutState.lineInfo().setFirstLine(!last);
-    layoutState.lineInfo().setPreviousLineBrokeCleanly(!last || last->endsWithBreak());
+    layoutState.lineInfo().setFirstLine(!lastLine);
+    layoutState.lineInfo().setPreviousLineBrokeCleanly(!lastLine || lastLine->endsWithBreak());
 
-    if (last) {
-        setLogicalHeight(last->lineBottomWithLeading());
-        InlineIterator iter = InlineIterator(this, last->lineBreakObj(), last->lineBreakPos());
+    if (lastLine) {
+        setLogicalHeight(lastLine->lineBottomWithLeading());
+        InlineIterator iter = InlineIterator(this, lastLine->lineBreakObj(), lastLine->lineBreakPos());
         resolver.setPosition(iter, numberOfIsolateAncestors(iter));
-        resolver.setStatus(last->lineBreakBidiStatus());
+        resolver.setStatus(lastLine->lineBreakBidiStatus());
     } else {
         TextDirection direction = style().direction();
         if (style().unicodeBidi() == Plaintext)
@@ -1875,44 +1929,59 @@ RootInlineBox* RenderBlockFlow::determineStartPosition(LineLayoutState& layoutSt
         InlineIterator iter = InlineIterator(this, bidiFirstSkippingEmptyInlines(*this, &resolver), 0);
         resolver.setPosition(iter, numberOfIsolateAncestors(iter));
     }
-    return curr;
+    return currentLine;
 }
 
 void RenderBlockFlow::determineEndPosition(LineLayoutState& layoutState, RootInlineBox* startLine, InlineIterator& cleanLineStart, BidiStatus& cleanLineBidiStatus)
 {
+    auto iteratorForFirstDirtyFloat = [](LineLayoutState::FloatList& floats) {
+        auto lastCleanFloat = floats.lastCleanFloat();
+        if (!lastCleanFloat)
+            return floats.begin();
+        auto* lastCleanFloatWithRect = floats.floatWithRect(*lastCleanFloat);
+        ASSERT(lastCleanFloatWithRect);
+        return ++floats.find(*lastCleanFloatWithRect);
+    };
+
     ASSERT(!layoutState.endLine());
-    size_t floatIndex = layoutState.floatIndex();
-    RootInlineBox* last = 0;
-    for (RootInlineBox* curr = startLine->nextRootBox(); curr; curr = curr->nextRootBox()) {
-        if (!curr->isDirty()) {
-            bool encounteredNewFloat = false;
-            bool dirtiedByFloat = false;
-            checkFloatsInCleanLine(curr, layoutState.floats(), floatIndex, encounteredNewFloat, dirtiedByFloat);
-            if (encounteredNewFloat)
-                return;
+    auto floatsIterator = iteratorForFirstDirtyFloat(layoutState.floatList());
+    auto end = layoutState.floatList().end();
+    RootInlineBox* lastLine = nullptr;
+    for (RootInlineBox* currentLine = startLine->nextRootBox(); currentLine; currentLine = currentLine->nextRootBox()) {
+        if (!currentLine->isDirty()) {
+            if (auto* cleanLineFloats = currentLine->floatsPtr()) {
+                bool encounteredNewFloat = false;
+                bool dirtiedByFloat = false;
+                for (auto* floatBoxOnCleanLine : *cleanLineFloats) {
+                    ASSERT(floatsIterator != end);
+                    checkFloatInCleanLine(*currentLine, *floatBoxOnCleanLine, *floatsIterator, encounteredNewFloat, dirtiedByFloat);
+                    ++floatsIterator;
+                    if (floatsIterator == end || encounteredNewFloat)
+                        return;
+                }
+            }
         }
-        if (curr->isDirty())
-            last = 0;
-        else if (!last)
-            last = curr;
+        if (currentLine->isDirty())
+            lastLine = nullptr;
+        else if (!lastLine)
+            lastLine = currentLine;
     }
 
-    if (!last)
+    if (!lastLine)
         return;
 
     // At this point, |last| is the first line in a run of clean lines that ends with the last line
     // in the block.
+    RootInlineBox* previousLine = lastLine->prevRootBox();
+    cleanLineStart = InlineIterator(this, previousLine->lineBreakObj(), previousLine->lineBreakPos());
+    cleanLineBidiStatus = previousLine->lineBreakBidiStatus();
+    layoutState.setEndLineLogicalTop(previousLine->lineBottomWithLeading());
 
-    RootInlineBox* prev = last->prevRootBox();
-    cleanLineStart = InlineIterator(this, prev->lineBreakObj(), prev->lineBreakPos());
-    cleanLineBidiStatus = prev->lineBreakBidiStatus();
-    layoutState.setEndLineLogicalTop(prev->lineBottomWithLeading());
-
-    for (RootInlineBox* line = last; line; line = line->nextRootBox())
-        line->extractLine(); // Disconnect all line boxes from their render objects while preserving
-                             // their connections to one another.
-
-    layoutState.setEndLine(last);
+    for (RootInlineBox* line = lastLine; line; line = line->nextRootBox()) {
+        // Disconnect all line boxes from their render objects while preserving their connections to one another.
+        line->extractLine();
+    }
+    layoutState.setEndLine(lastLine);
 }
 
 bool RenderBlockFlow::checkPaginationAndFloatsAtEndLine(LineLayoutState& layoutState)
@@ -1928,8 +1997,9 @@ bool RenderBlockFlow::checkPaginationAndFloatsAtEndLine(LineLayoutState& layoutS
                 // This isn't the real move we're going to do, so don't update the line box's pagination
                 // strut yet.
                 LayoutUnit oldPaginationStrut = lineBox->paginationStrut();
+                bool overflowsRegion;
                 lineDelta -= oldPaginationStrut;
-                adjustLinePositionForPagination(lineBox, lineDelta, layoutState.flowThread());
+                adjustLinePositionForPagination(lineBox, lineDelta, overflowsRegion, layoutState.flowThread());
                 lineBox->setPaginationStrut(oldPaginationStrut);
             }
             if (lineWidthForPaginatedLineChanged(lineBox, lineDelta, layoutState.flowThread()))
@@ -1952,7 +2022,7 @@ bool RenderBlockFlow::checkPaginationAndFloatsAtEndLine(LineLayoutState& layoutS
     const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
     auto end = floatingObjectSet.end();
     for (auto it = floatingObjectSet.begin(); it != end; ++it) {
-        FloatingObject* floatingObject = it->get();
+        const auto& floatingObject = *it->get();
         if (logicalBottomForFloat(floatingObject) >= logicalTop && logicalBottomForFloat(floatingObject) < logicalBottom)
             return false;
     }
@@ -1982,11 +2052,11 @@ bool RenderBlockFlow::matchedEndLine(LineLayoutState& layoutState, const InlineB
 
     // The first clean line doesn't match, but we can check a handful of following lines to try
     // to match back up.
-    static int numLines = 8; // The # of lines we're willing to match against.
+    static const int numLines = 8; // The # of lines we're willing to match against.
     RootInlineBox* originalEndLine = layoutState.endLine();
     RootInlineBox* line = originalEndLine;
     for (int i = 0; i < numLines && line; i++, line = line->nextRootBox()) {
-        if (line->lineBreakObj() == resolver.position().renderer() && line->lineBreakPos() == resolver.position().offset()) {
+        if (line->lineBreakObj() == resolver.position().renderer() && line->lineBreakPos() == resolver.position().offset() && !line->hasAnonymousInlineBlock()) {
             // We have a match.
             if (line->lineBreakBidiStatus() != resolver.status())
                 return false; // ...but the bidi state doesn't match.
@@ -2033,13 +2103,14 @@ void RenderBlockFlow::addOverflowFromInlineChildren()
         endPadding = 1;
     for (RootInlineBox* curr = firstRootBox(); curr; curr = curr->nextRootBox()) {
         addLayoutOverflow(curr->paddedLayoutOverflowRect(endPadding));
-        RenderRegion* region = curr->containingRegion();
+        RenderRegion* region = flowThreadContainingBlock() ? curr->containingRegion() : nullptr;
         if (region)
             region->addLayoutOverflowForBox(this, curr->paddedLayoutOverflowRect(endPadding));
         if (!hasOverflowClip()) {
-            addVisualOverflow(curr->visualOverflowRect(curr->lineTop(), curr->lineBottom()));
+            LayoutRect childVisualOverflowRect = curr->visualOverflowRect(curr->lineTop(), curr->lineBottom());
+            addVisualOverflow(childVisualOverflowRect);
             if (region)
-                region->addVisualOverflowForBox(this, curr->visualOverflowRect(curr->lineTop(), curr->lineBottom()));
+                region->addVisualOverflowForBox(this, childVisualOverflowRect);
         }
     }
 }
@@ -2048,23 +2119,23 @@ void RenderBlockFlow::deleteEllipsisLineBoxes()
 {
     ETextAlign textAlign = style().textAlign();
     bool ltr = style().isLeftToRightDirection();
-    bool firstLine = true;
+    IndentTextOrNot shouldIndentText = IndentText;
     for (RootInlineBox* curr = firstRootBox(); curr; curr = curr->nextRootBox()) {
         if (curr->hasEllipsisBox()) {
             curr->clearTruncation();
 
             // Shift the line back where it belongs if we cannot accomodate an ellipsis.
-            float logicalLeft = pixelSnappedLogicalLeftOffsetForLine(curr->lineTop(), firstLine);
-            float availableLogicalWidth = logicalRightOffsetForLine(curr->lineTop(), false) - logicalLeft;
+            float logicalLeft = logicalLeftOffsetForLine(curr->lineTop(), shouldIndentText);
+            float availableLogicalWidth = logicalRightOffsetForLine(curr->lineTop(), DoNotIndentText) - logicalLeft;
             float totalLogicalWidth = curr->logicalWidth();
-            updateLogicalWidthForAlignment(textAlign, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);
+            updateLogicalWidthForAlignment(textAlign, curr, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);
 
             if (ltr)
                 curr->adjustLogicalPosition((logicalLeft - curr->logicalLeft()), 0);
             else
                 curr->adjustLogicalPosition(-(curr->logicalLeft() - logicalLeft), 0);
         }
-        firstLine = false;
+        shouldIndentText = DoNotIndentText;
     }
 }
 
@@ -2072,11 +2143,11 @@ void RenderBlockFlow::checkLinesForTextOverflow()
 {
     // Determine the width of the ellipsis using the current font.
     // FIXME: CSS3 says this is configurable, also need to use 0x002E (FULL STOP) if horizontal ellipsis is "not renderable"
-    const Font& font = style().font();
-    DEFINE_STATIC_LOCAL(AtomicString, ellipsisStr, (&horizontalEllipsis, 1));
-    const Font& firstLineFont = firstLineStyle().font();
-    int firstLineEllipsisWidth = firstLineFont.width(constructTextRun(this, firstLineFont, &horizontalEllipsis, 1, firstLineStyle()));
-    int ellipsisWidth = (font == firstLineFont) ? firstLineEllipsisWidth : font.width(constructTextRun(this, font, &horizontalEllipsis, 1, style()));
+    const FontCascade& font = style().fontCascade();
+    static NeverDestroyed<AtomicString> ellipsisStr(&horizontalEllipsis, 1);
+    const FontCascade& firstLineFont = firstLineStyle().fontCascade();
+    float firstLineEllipsisWidth = firstLineFont.width(constructTextRun(&horizontalEllipsis, 1, firstLineStyle()));
+    float ellipsisWidth = (font == firstLineFont) ? firstLineEllipsisWidth : font.width(constructTextRun(&horizontalEllipsis, 1, style()));
 
     // For LTR text truncation, we want to get the right edge of our padding box, and then we want to see
     // if the right edge of a line box exceeds that.  For RTL, we use the left edge of the padding box and
@@ -2086,25 +2157,23 @@ void RenderBlockFlow::checkLinesForTextOverflow()
     ETextAlign textAlign = style().textAlign();
     bool firstLine = true;
     for (RootInlineBox* curr = firstRootBox(); curr; curr = curr->nextRootBox()) {
-        // FIXME: Use pixelSnappedLogicalRightOffsetForLine instead of snapping it ourselves once the column workaround in said method has been fixed.
-        // https://bugs.webkit.org/show_bug.cgi?id=105461
-        int blockRightEdge = snapSizeToPixel(logicalRightOffsetForLine(curr->lineTop(), firstLine), curr->x());
-        int blockLeftEdge = pixelSnappedLogicalLeftOffsetForLine(curr->lineTop(), firstLine);
-        int lineBoxEdge = ltr ? snapSizeToPixel(curr->x() + curr->logicalWidth(), curr->x()) : snapSizeToPixel(curr->x(), 0);
+        IndentTextOrNot shouldIndentText = firstLine ? IndentText : DoNotIndentText;
+        LayoutUnit blockRightEdge = logicalRightOffsetForLine(curr->lineTop(), shouldIndentText);
+        LayoutUnit blockLeftEdge = logicalLeftOffsetForLine(curr->lineTop(), shouldIndentText);
+        LayoutUnit lineBoxEdge = ltr ? curr->x() + curr->logicalWidth() : curr->x();
         if ((ltr && lineBoxEdge > blockRightEdge) || (!ltr && lineBoxEdge < blockLeftEdge)) {
             // This line spills out of our box in the appropriate direction.  Now we need to see if the line
             // can be truncated.  In order for truncation to be possible, the line must have sufficient space to
             // accommodate our truncation string, and no replaced elements (images, tables) can overlap the ellipsis
             // space.
-
             LayoutUnit width = firstLine ? firstLineEllipsisWidth : ellipsisWidth;
             LayoutUnit blockEdge = ltr ? blockRightEdge : blockLeftEdge;
             if (curr->lineCanAccommodateEllipsis(ltr, blockEdge, lineBoxEdge, width)) {
                 float totalLogicalWidth = curr->placeEllipsis(ellipsisStr, ltr, blockLeftEdge, blockRightEdge, width);
 
                 float logicalLeft = 0; // We are only interested in the delta from the base position.
-                float truncatedWidth = pixelSnappedLogicalRightOffsetForLine(curr->lineTop(), firstLine);
-                updateLogicalWidthForAlignment(textAlign, 0, logicalLeft, totalLogicalWidth, truncatedWidth, 0);
+                float truncatedWidth = availableLogicalWidthForLine(curr->lineTop(), shouldIndentText);
+                updateLogicalWidthForAlignment(textAlign, curr, nullptr, logicalLeft, totalLogicalWidth, truncatedWidth, 0);
                 if (ltr)
                     curr->adjustLogicalPosition(logicalLeft, 0);
                 else
@@ -2115,7 +2184,7 @@ void RenderBlockFlow::checkLinesForTextOverflow()
     }
 }
 
-bool RenderBlockFlow::positionNewFloatOnLine(FloatingObject* newFloat, FloatingObject* lastFloatFromPreviousLine, LineInfo& lineInfo, LineWidth& width)
+bool RenderBlockFlow::positionNewFloatOnLine(const FloatingObject& newFloat, FloatingObject* lastFloatFromPreviousLine, LineInfo& lineInfo, LineWidth& width)
 {
     if (!positionNewFloats())
         return false;
@@ -2125,14 +2194,14 @@ bool RenderBlockFlow::positionNewFloatOnLine(FloatingObject* newFloat, FloatingO
     // We only connect floats to lines for pagination purposes if the floats occur at the start of
     // the line and the previous line had a hard break (so this line is either the first in the block
     // or follows a <br>).
-    if (!newFloat->paginationStrut() || !lineInfo.previousLineBrokeCleanly() || !lineInfo.isEmpty())
+    if (!newFloat.paginationStrut() || !lineInfo.previousLineBrokeCleanly() || !lineInfo.isEmpty())
         return true;
 
     const FloatingObjectSet& floatingObjectSet = m_floatingObjects->set();
-    ASSERT(floatingObjectSet.last().get() == newFloat);
+    ASSERT(floatingObjectSet.last().get() == &newFloat);
 
     LayoutUnit floatLogicalTop = logicalTopForFloat(newFloat);
-    int paginationStrut = newFloat->paginationStrut();
+    LayoutUnit paginationStrut = newFloat.paginationStrut();
 
     if (floatLogicalTop - paginationStrut != logicalHeight() + lineInfo.floatPaginationStrut())
         return true;
@@ -2142,26 +2211,26 @@ bool RenderBlockFlow::positionNewFloatOnLine(FloatingObject* newFloat, FloatingO
     auto begin = floatingObjectSet.begin();
     while (it != begin) {
         --it;
-        FloatingObject* floatingObject = it->get();
-        if (floatingObject == lastFloatFromPreviousLine)
+        auto& floatingObject = *it->get();
+        if (&floatingObject == lastFloatFromPreviousLine)
             break;
         if (logicalTopForFloat(floatingObject) == logicalHeight() + lineInfo.floatPaginationStrut()) {
-            floatingObject->setPaginationStrut(paginationStrut + floatingObject->paginationStrut());
-            RenderBox& floatBox = floatingObject->renderer();
+            floatingObject.setPaginationStrut(paginationStrut + floatingObject.paginationStrut());
+            RenderBox& floatBox = floatingObject.renderer();
             setLogicalTopForChild(floatBox, logicalTopForChild(floatBox) + marginBeforeForChild(floatBox) + paginationStrut);
 
-            if (updateRegionRangeForBoxChild(floatingObject->renderer()))
+            if (updateRegionRangeForBoxChild(floatBox))
                 floatBox.setNeedsLayout(MarkOnlyThis);
-            else if (floatBox.isRenderBlock())
-                toRenderBlock(floatBox).setChildNeedsLayout(MarkOnlyThis);
+            else if (is<RenderBlock>(floatBox))
+                downcast<RenderBlock>(floatBox).setChildNeedsLayout(MarkOnlyThis);
             floatBox.layoutIfNeeded();
 
             // Save the old logical top before calling removePlacedObject which will set
             // isPlaced to false. Otherwise it will trigger an assert in logicalTopForFloat.
             LayoutUnit oldLogicalTop = logicalTopForFloat(floatingObject);
-            m_floatingObjects->removePlacedObject(floatingObject);
+            m_floatingObjects->removePlacedObject(&floatingObject);
             setLogicalTopForFloat(floatingObject, oldLogicalTop + paginationStrut);
-            m_floatingObjects->addPlacedObject(floatingObject);
+            m_floatingObjects->addPlacedObject(&floatingObject);
         }
     }
 
@@ -2171,22 +2240,39 @@ bool RenderBlockFlow::positionNewFloatOnLine(FloatingObject* newFloat, FloatingO
     return true;
 }
 
-LayoutUnit RenderBlockFlow::startAlignedOffsetForLine(LayoutUnit position, bool firstLine)
+LayoutUnit RenderBlockFlow::startAlignedOffsetForLine(LayoutUnit position, IndentTextOrNot shouldIndentText)
 {
     ETextAlign textAlign = style().textAlign();
-
+    bool shouldApplyIndentText = false;
+    switch (textAlign) {
+    case LEFT:
+    case WEBKIT_LEFT:
+        shouldApplyIndentText = style().isLeftToRightDirection();
+        break;
+    case RIGHT:
+    case WEBKIT_RIGHT:
+        shouldApplyIndentText = !style().isLeftToRightDirection();
+        break;
+    case TASTART:
+        shouldApplyIndentText = true;
+        break;
+    default:
+        shouldApplyIndentText = false;
+    }
     // <rdar://problem/15427571>
     // https://bugs.webkit.org/show_bug.cgi?id=124522
     // This quirk is for legacy content that doesn't work properly with the center positioning scheme
     // being honored (e.g., epubs).
-    if (textAlign == TASTART || document().settings()->useLegacyTextAlignPositionedElementBehavior()) // FIXME: Handle TAEND here
-        return startOffsetForLine(position, firstLine);
+    if (shouldApplyIndentText || settings().useLegacyTextAlignPositionedElementBehavior()) // FIXME: Handle TAEND here
+        return startOffsetForLine(position, shouldIndentText);
 
     // updateLogicalWidthForAlignment() handles the direction of the block so no need to consider it here
     float totalLogicalWidth = 0;
-    float logicalLeft = logicalLeftOffsetForLine(logicalHeight(), false);
-    float availableLogicalWidth = logicalRightOffsetForLine(logicalHeight(), false) - logicalLeft;
-    updateLogicalWidthForAlignment(textAlign, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);
+    float logicalLeft = logicalLeftOffsetForLine(logicalHeight(), DoNotIndentText);
+    float availableLogicalWidth = logicalRightOffsetForLine(logicalHeight(), DoNotIndentText) - logicalLeft;
+
+    // FIXME: Bug 129311: We need to pass a valid RootInlineBox here, considering the bidi level used to construct the line.
+    updateLogicalWidthForAlignment(textAlign, 0, 0, logicalLeft, totalLogicalWidth, availableLogicalWidth, 0);
 
     if (!style().isLeftToRightDirection())
         return logicalWidth() - logicalLeft;
@@ -2197,10 +2283,14 @@ void RenderBlockFlow::updateRegionForLine(RootInlineBox* lineBox) const
 {
     ASSERT(lineBox);
 
-    if (auto containingRegion = regionAtBlockOffset(lineBox->lineTopWithLeading()))
-        lineBox->setContainingRegion(*containingRegion);
-    else
+    if (!hasRegionRangeInFlowThread())
         lineBox->clearContainingRegion();
+    else {
+        if (auto containingRegion = regionAtBlockOffset(lineBox->lineTopWithLeading()))
+            lineBox->setContainingRegion(*containingRegion);
+        else
+            lineBox->clearContainingRegion();
+    }
 
     RootInlineBox* prevLineBox = lineBox->prevRootBox();
     if (!prevLineBox)
@@ -2213,4 +2303,46 @@ void RenderBlockFlow::updateRegionForLine(RootInlineBox* lineBox) const
         lineBox->setIsFirstAfterPageBreak(true);
 }
 
+void RenderBlockFlow::marginCollapseLinesFromStart(LineLayoutState& layoutState, RootInlineBox* stopLine)
+{
+    // We have to handle an anonymous inline block streak at the start of the block in order to make sure our own margins are
+    // correct. We only have to do this if the children can propagate margins out to us.
+    bool resetLogicalHeight = false;
+    if (layoutState.marginInfo().canCollapseWithMarginBefore()) {
+        RootInlineBox* startLine = firstRootBox();
+        RootInlineBox* curr;
+        for (curr = startLine; curr && curr->hasAnonymousInlineBlock() && layoutState.marginInfo().canCollapseWithMarginBefore(); curr = curr->nextRootBox()) {
+            if (curr == stopLine)
+                return;
+            if (!resetLogicalHeight) {
+                setLogicalHeight(borderAndPaddingBefore());
+                resetLogicalHeight = true;
+            }
+            layoutBlockChild(*curr->anonymousInlineBlock(), layoutState.marginInfo(),
+                layoutState.prevFloatBottomFromAnonymousInlineBlock(), layoutState.maxFloatBottomFromAnonymousInlineBlock());
+        }
+    }
+    
+    // Now that we've handled the top of the block, if the stopLine isn't an anonymous block, then we're done.
+    if (!stopLine->hasAnonymousInlineBlock())
+        return;
+
+    // We already handled top of block with startLine.
+    if (stopLine == firstRootBox())
+        return;
+
+    // Re-run margin collapsing on the block sequence that stopLine is a part of.
+    // First go backwards to get the entire sequence.
+    RootInlineBox* prev = stopLine;
+    for ( ; prev->hasAnonymousInlineBlock(); prev = prev->prevRootBox()) {
+    };
+
+    // Update the block height to the correct state.
+    setLogicalHeight(prev->lineBottomWithLeading());
+    
+    // Now run margin collapsing on those lines.
+    for (prev = prev->nextRootBox(); prev != stopLine; prev = prev->nextRootBox())
+        layoutBlockChild(*prev->anonymousInlineBlock(), layoutState.marginInfo(), layoutState.prevFloatBottomFromAnonymousInlineBlock(), layoutState.maxFloatBottomFromAnonymousInlineBlock());
+}
+
 }