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

Source/core/rendering/RenderFlowThread.cpp

 /*
  * Copyright (C) 2011 Adobe Systems Incorporated. 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.
@@ skipping 344 matching lines @@
     RenderRegionRangeMap::const_iterator it = m_regionRangeMap.find(box);
     if (it == m_regionRangeMap.end())
         return;
 
     const RenderRegionRange& range = it->value;
     startRegion = range.startRegion();
     endRegion = range.endRegion();
     ASSERT(m_regionList.contains(startRegion) && m_regionList.contains(endRegion));
 }
 
-void RenderFlowThread::applyBreakAfterContent(LayoutUnit clientHeight)
-{
-    // Simulate a region break at height. If it points inside an auto logical height region,
-    // then it may determine the region computed autoheight.
-    addForcedRegionBreak(clientHeight, this, false);
-}
-
 void RenderFlowThread::updateRegionsFlowThreadPortionRect()
 {
     LayoutUnit logicalHeight = 0;
     // FIXME: Optimize not to clear the interval all the time. This implies manually managing the tree nodes lifecycle.
     m_regionIntervalTree.clear();
     m_regionIntervalTree.initIfNeeded();
     for (RenderRegionList::iterator iter = m_regionList.begin(); iter != m_regionList.end(); ++iter) {
         RenderRegion* region = *iter;
 
         LayoutUnit regionLogicalWidth = region->pageLogicalWidth();
@@ skipping 163 matching lines @@
 {
     if (!m_renderFlowThread)
         return;
     RenderView* view = m_renderFlowThread->view();
     ASSERT(view->flowThreadController()->currentRenderFlowThread() == m_renderFlowThread);
     view->flowThreadController()->setCurrentRenderFlowThread(m_previousRenderFlowThread);
 }
 
 
 } // namespace WebCore