[New Multicolumn] Preparatory work for nested multicol support.

Source/core/rendering/RenderFlowThread.h

 /*
  * 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 104 matching lines @@
     }
 
     // Used to estimate the maximum height of the flow thread.
     static LayoutUnit maxLogicalHeight() { return LayoutUnit::max() / 2; }
 
     virtual RenderMultiColumnSet* columnSetAtBlockOffset(LayoutUnit) const = 0;
 
 protected:
     virtual const char* renderName() const = 0;
 
-    void updateRegionsFlowThreadPortionRect();
+    void generateColumnSetIntervalTree();
 
     RenderMultiColumnSetList m_multiColumnSetList;
 
     typedef PODInterval<LayoutUnit, RenderMultiColumnSet*> MultiColumnSetInterval;
     typedef PODIntervalTree<LayoutUnit, RenderMultiColumnSet*> MultiColumnSetIntervalTree;
 
     class MultiColumnSetSearchAdapter {
     public:
         MultiColumnSetSearchAdapter(LayoutUnit offset)
             : m_offset(offset)
@@ skipping 28 matching lines @@
 };
 
 template <> struct ValueToString<RenderMultiColumnSet*> {
     static String string(const RenderMultiColumnSet* value) { return String::format("%p", value); }
 };
 #endif
 
 } // namespace blink
 
 #endif // RenderFlowThread_h