Replace RenderArena with PartitionAlloc.

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 24 matching lines @@
 {
     setFlowThreadState(InsideInFlowThread);
 }
 
 RenderMultiColumnFlowThread::~RenderMultiColumnFlowThread()
 {
 }
 
 RenderMultiColumnFlowThread* RenderMultiColumnFlowThread::createAnonymous(Document* document)
 {
-    RenderMultiColumnFlowThread* renderer = new (document->renderArena()) RenderMultiColumnFlowThread();
+    RenderMultiColumnFlowThread* renderer = new RenderMultiColumnFlowThread();
     renderer->setDocumentForAnonymous(document);
     return renderer;
 }
 
 const char* RenderMultiColumnFlowThread::renderName() const
 {    
     return "RenderMultiColumnFlowThread";
 }
 
 void RenderMultiColumnFlowThread::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues& computedValues) const
@@ skipping 43 matching lines @@
     // Even though we aren't placed yet, we can go ahead and set up our size.
     firstSet->updateLogicalWidth();
     firstSet->updateLogicalHeight();
 
     firstSet->setRequiresBalancing(parentBlock->requiresBalancing());
     
     validateRegions();
 }
 
 }