Remove line breaking to avoid window.

Now that we don't have multi-column or pagination, this
is dead code. This also means we don't need to call
layoutBlockFlow in a loop.

R=esprehn@chromium.org

Review URL: https://codereview.chromium.org/697713002

engine/core/rendering/RenderBlockFlow.cpp

@@ -161,42 +161,6 @@ bool RenderBlockFlow::updateLogicalWidthAndColumnWidth()
     return RenderBlock::updateLogicalWidthAndColumnWidth();
 }
 
-void RenderBlockFlow::setBreakAtLineToAvoidWidow(int lineToBreak)
-{
-    ASSERT(lineToBreak >= 0);
-    ensureRareData();
-    ASSERT(!m_rareData->m_didBreakAtLineToAvoidWidow);
-    m_rareData->m_lineBreakToAvoidWidow = lineToBreak;
-}
-
-void RenderBlockFlow::setDidBreakAtLineToAvoidWidow()
-{
-    ASSERT(!shouldBreakAtLineToAvoidWidow());
-
-    // This function should be called only after a break was applied to avoid widows
-    // so assert |m_rareData| exists.
-    ASSERT(m_rareData);
-
-    m_rareData->m_didBreakAtLineToAvoidWidow = true;
-}
-
-void RenderBlockFlow::clearDidBreakAtLineToAvoidWidow()
-{
-    if (!m_rareData)
-        return;
-
-    m_rareData->m_didBreakAtLineToAvoidWidow = false;
-}
-
-void RenderBlockFlow::clearShouldBreakAtLineToAvoidWidow() const
-{
-    ASSERT(shouldBreakAtLineToAvoidWidow());
-    if (!m_rareData)
-        return;
-
-    m_rareData->m_lineBreakToAvoidWidow = -1;
-}
-
 bool RenderBlockFlow::isSelfCollapsingBlock() const
 {
     m_hasOnlySelfCollapsingChildren = RenderBlock::isSelfCollapsingBlock();
@@ -218,13 +182,7 @@ void RenderBlockFlow::layoutBlock(bool relayoutChildren)
 
     SubtreeLayoutScope layoutScope(*this);
 
-    // Multiple passes might be required for column and pagination based layout
-    // In the case of the old column code the number of passes will only be two
-    // however, in the newer column code the number of passes could equal the
-    // number of columns.
-    bool done = false;
-    while (!done)
-        done = layoutBlockFlow(relayoutChildren, layoutScope);
+    layoutBlockFlow(relayoutChildren, layoutScope);
 
     updateLayerTransformAfterLayout();
 
@@ -238,7 +196,7 @@ void RenderBlockFlow::layoutBlock(bool relayoutChildren)
     clearNeedsLayout();
 }
 
-inline bool RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, SubtreeLayoutScope& layoutScope)
+inline void RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, SubtreeLayoutScope& layoutScope)
 {
     LayoutUnit oldLeft = logicalLeft();
     bool logicalWidthChanged = updateLogicalWidthAndColumnWidth();
@@ -278,11 +236,6 @@ inline bool RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, SubtreeLayou
     if (lowestFloatLogicalBottom() > (logicalHeight() - afterEdge) && createsBlockFormattingContext())
         setLogicalHeight(lowestFloatLogicalBottom() + afterEdge);
 
-    if (shouldBreakAtLineToAvoidWidow()) {
-        setEverHadLayout(true);
-        return false;
-    }
-
     // Calculate our new height.
     LayoutUnit oldHeight = logicalHeight();
     LayoutUnit oldClientAfterEdge = clientLogicalBottom();
@@ -311,7 +264,6 @@ inline bool RenderBlockFlow::layoutBlockFlow(bool relayoutChildren, SubtreeLayou
     computeOverflow(oldClientAfterEdge);
 
     m_descendantsWithFloatsMarkedForLayout = false;
-    return true;
 }
 
 void RenderBlockFlow::determineLogicalLeftPositionForChild(RenderBox* child)

engine/core/rendering/RenderBlockFlow.h

@@ -156,7 +156,7 @@ protected:
     void determineLogicalLeftPositionForChild(RenderBox* child);
 
 private:
-    bool layoutBlockFlow(bool relayoutChildren, SubtreeLayoutScope&);
+    void layoutBlockFlow(bool relayoutChildren, SubtreeLayoutScope&);
     void layoutBlockChildren(bool relayoutChildren, SubtreeLayoutScope&, LayoutUnit beforeEdge, LayoutUnit afterEdge);
 
     void layoutBlockChild(RenderBox* child, MarginInfo&, LayoutUnit& previousFloatLogicalBottom);
@@ -199,14 +199,6 @@ private:
 
     void updateLogicalWidthForAlignment(const ETextAlign&, const RootInlineBox*, BidiRun* trailingSpaceRun, float& logicalLeft, float& totalLogicalWidth, float& availableLogicalWidth, unsigned expansionOpportunityCount);
 
-    bool shouldBreakAtLineToAvoidWidow() const { return m_rareData && m_rareData->m_lineBreakToAvoidWidow >= 0; }
-    void clearShouldBreakAtLineToAvoidWidow() const;
-    int lineBreakToAvoidWidow() const { return m_rareData ? m_rareData->m_lineBreakToAvoidWidow : -1; }
-    void setBreakAtLineToAvoidWidow(int);
-    void clearDidBreakAtLineToAvoidWidow();
-    void setDidBreakAtLineToAvoidWidow();
-    bool didBreakAtLineToAvoidWidow() const { return m_rareData && m_rareData->m_didBreakAtLineToAvoidWidow; }
-
 public:
     struct FloatWithRect {
         FloatWithRect(RenderBox* f)
@@ -254,8 +246,6 @@ public:
     public:
         RenderBlockFlowRareData(const RenderBlockFlow* block)
             : m_margins(positiveMarginBeforeDefault(block), negativeMarginBeforeDefault(block), positiveMarginAfterDefault(block), negativeMarginAfterDefault(block))
-            , m_lineBreakToAvoidWidow(-1)
-            , m_didBreakAtLineToAvoidWidow(false)
             , m_discardMarginBefore(false)
             , m_discardMarginAfter(false)
         {
@@ -280,9 +270,6 @@ public:
         }
 
         MarginValues m_margins;
-
-        int m_lineBreakToAvoidWidow;
-        bool m_didBreakAtLineToAvoidWidow : 1;
         bool m_discardMarginBefore : 1;
         bool m_discardMarginAfter : 1;
     };

engine/core/rendering/RenderBlockLineLayout.cpp

@@ -800,8 +800,6 @@ void RenderBlockFlow::layoutRunsAndFloatsInRange(LineLayoutState& layoutState,
         lineMidpointState.reset();
         resolver.setPosition(endOfLine, numberOfIsolateAncestors(endOfLine));
     }
-
-    clearDidBreakAtLineToAvoidWidow();
 }
 
 void RenderBlockFlow::linkToEndLineIfNeeded(LineLayoutState& layoutState)