Move widow-avoiding code from RenderBlock down to RenderBlockFlow.

Source/core/rendering/RenderBlockFlow.cpp

 /*
  * Copyright (C) 2013 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 262 matching lines @@
     ColumnInfo* colInfo = columnInfo();
     if (pageLogicalHeight)
         colInfo->setColumnCountAndHeight(count, pageLogicalHeight);
 
     if (columnCount(colInfo)) {
         setLogicalHeight(borderBefore() + paddingBefore() + colInfo->columnHeight() + borderAfter() + paddingAfter() + scrollbarLogicalHeight());
         m_overflow.clear();
     }
 }
 
+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();
     return m_hasOnlySelfCollapsingChildren;
 }
 
 void RenderBlockFlow::layoutBlock(bool relayoutChildren)
 {
     ASSERT(needsLayout());
     ASSERT(isInlineBlockOrInlineTable() || !isInline());
@@ skipping 257 matching lines @@
     if (paginated) {
         logicalTopAfterClear = adjustBlockChildForPagination(logicalTopAfterClear, estimateWithoutPagination, child,
             atBeforeSideOfBlock && logicalTopBeforeClear == logicalTopAfterClear);
     }
 
     setLogicalTopForChild(child, logicalTopAfterClear);
 
     // Now we have a final top position. See if it really does end up being different from our estimate.
     // clearFloatsIfNeeded can also mark the child as needing a layout even though we didn't move. This happens
     // when collapseMargins dynamically adds overhanging floats because of a child with negative margins.
-    if (logicalTopAfterClear != logicalTopEstimate || child->needsLayout() || (paginated && childRenderBlock && childRenderBlock->shouldBreakAtLineToAvoidWidow())) {
+    if (logicalTopAfterClear != logicalTopEstimate || child->needsLayout() || (paginated && childRenderBlockFlow && childRenderBlockFlow->shouldBreakAtLineToAvoidWidow())) {
         SubtreeLayoutScope layoutScope(*child);
         if (child->shrinkToAvoidFloats()) {
             // The child's width depends on the line width.
             // When the child shifts to clear an item, its width can
             // change (because it has more available line width).
             // So go ahead and mark the item as dirty.
             layoutScope.setChildNeedsLayout(child);
         }
 
         if (childRenderBlock) {
@@ skipping 2329 matching lines @@
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareData()
 {
     if (m_rareData)
         return *m_rareData;
 
     m_rareData = adoptPtr(new RenderBlockFlowRareData(this));
     return *m_rareData;
 }
 
 } // namespace WebCore