[New Multicolumn] Make fast/multicol/overflow-content.html pass in the new implementation.

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 402 matching lines @@
 
     if (shouldBreakAtLineToAvoidWidow()) {
         setEverHadLayout(true);
         return false;
     }
 
     // Calculate our new height.
     LayoutUnit oldHeight = logicalHeight();
     LayoutUnit oldClientAfterEdge = clientLogicalBottom();
 
-    if (isRenderFlowThread())
-        toRenderFlowThread(this)->applyBreakAfterContent(oldClientAfterEdge);
-
     updateLogicalHeight();
     LayoutUnit newHeight = logicalHeight();
     if (oldHeight > newHeight && !childrenInline()) {
         // One of our children's floats may have become an overhanging float for us.
         for (RenderObject* child = lastChild(); child; child = child->previousSibling()) {
             if (child->isRenderBlockFlow() && !child->isFloatingOrOutOfFlowPositioned()) {
                 RenderBlockFlow* block = toRenderBlockFlow(child);
                 if (block->lowestFloatLogicalBottom() + block->logicalTop() <= newHeight)
                     break;
                 addOverhangingFloats(block, false);
@@ skipping 2360 matching lines @@
 RenderBlockFlow::RenderBlockFlowRareData& RenderBlockFlow::ensureRareData()
 {
     if (m_rareData)
         return *m_rareData;
 
     m_rareData = adoptPtr(new RenderBlockFlowRareData(this));
     return *m_rareData;
 }
 
 } // namespace WebCore