[New Multicolumn] Create RenderMultiColumnSet during renderer creation, not during layout.

Source/core/rendering/RenderBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 4691 matching lines @@
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 RenderRegion* RenderBlock::regionAtBlockOffset(LayoutUnit blockOffset) const
 {
     RenderFlowThread* flowThread = flowThreadContainingBlock();
     if (!flowThread || !flowThread->hasValidRegionInfo())
         return 0;
 
-    return flowThread->regionAtBlockOffset(offsetFromLogicalTopOfFirstPage() + blockOffset, true);
+    return flowThread->regionAtBlockOffset(offsetFromLogicalTopOfFirstPage() + blockOffset);
 }
 
 LayoutUnit RenderBlock::collapsedMarginBeforeForChild(const RenderBox* child) const
 {
     // If the child has the same directionality as we do, then we can just return its
     // collapsed margin.
     if (!child->isWritingModeRoot())
         return child->collapsedMarginBefore();
 
     // The child has a different directionality.  If the child is parallel, then it's just
@@ skipping 231 matching lines @@
 void RenderBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const RenderObject* obj) const
 {
     showRenderObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace WebCore