[Slimming paint] [New Multicolumn] Repaint column rules when they change.

Source/core/rendering/RenderMultiColumnFlowThread.cpp

 /*
  * Copyright (C) 2012 Apple 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:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 198 matching lines @@
         }
     }
 
     if (needsRelayout)
         setChildNeedsLayout(MarkOnlyThis);
 
     m_inBalancingPass = needsRelayout;
     return needsRelayout;
 }
 
+void RenderMultiColumnFlowThread::columnRuleStyleDidChange()
+{
+    for (RenderMultiColumnSet* columnSet = firstMultiColumnSet(); columnSet; columnSet = columnSet->nextSiblingMultiColumnSet())
+        columnSet->setShouldDoFullPaintInvalidation(PaintInvalidationStyleChange);
+}
+
 void RenderMultiColumnFlowThread::calculateColumnCountAndWidth(LayoutUnit& width, unsigned& count) const
 {
     RenderBlock* columnBlock = multiColumnBlockFlow();
     const RenderStyle* columnStyle = columnBlock->style();
     LayoutUnit availableWidth = columnBlock->contentLogicalWidth();
     LayoutUnit columnGap = columnBlock->columnGap();
     LayoutUnit computedColumnWidth = max<LayoutUnit>(1, LayoutUnit(columnStyle->columnWidth()));
     unsigned computedColumnCount = max<int>(1, columnStyle->columnCount());
 
     ASSERT(!columnStyle->hasAutoColumnCount() || !columnStyle->hasAutoColumnWidth());
@@ skipping 205 matching lines @@
 }
 
 bool RenderMultiColumnFlowThread::isPageLogicalHeightKnown() const
 {
     if (RenderMultiColumnSet* columnSet = lastMultiColumnSet())
         return columnSet->pageLogicalHeight();
     return false;
 }
 
 }