[New Multicolumn] Remove RenderRegionSet.

Source/core/rendering/RenderRegion.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 44 matching lines @@
 
     RenderFlowThread* flowThread() const { return m_flowThread; }
 
     // Valid regions do not create circular dependencies with other flows.
     bool isValid() const { return m_isValid; }
     void setIsValid(bool valid) { m_isValid = valid; }
 
     bool isFirstRegion() const;
     bool isLastRegion() const;
 
-    // These methods represent the width and height of a "page" and for a RenderRegion they are just the
-    // content width and content height of a region. For RenderRegionSets, however, they will be the width and
-    // height of a single column or page in the set.
+    // These methods represent the width and height of a "page" and for a RenderRegion they are just
+    // the content width and content height of a region. For RenderMultiColumnSets, however, they
+    // will be the width and height of a single column or page in the set.
     virtual LayoutUnit pageLogicalWidth() const;
     virtual LayoutUnit pageLogicalHeight() const;
 
     LayoutUnit logicalTopOfFlowThreadContentRect(const LayoutRect&) const;
     LayoutUnit logicalBottomOfFlowThreadContentRect(const LayoutRect&) const;
     LayoutUnit logicalTopForFlowThreadContent() const { return logicalTopOfFlowThreadContentRect(flowThreadPortionRect()); };
     LayoutUnit logicalBottomForFlowThreadContent() const { return logicalBottomOfFlowThreadContentRect(flowThreadPortionRect()); };
 
     // This method represents the logical height of the entire flow thread portion used by the region or set.
     // For RenderRegions it matches logicalPaginationHeight(), but for sets it is the height of all the pages
     // or columns added together.
     virtual LayoutUnit logicalHeightOfAllFlowThreadContent() const;
 
     // The top of the nearest page inside the region. For RenderRegions, this is just the logical top of the
     // flow thread portion we contain. For sets, we have to figure out the top of the nearest column or
     // page.
     virtual LayoutUnit pageLogicalTopForOffset(LayoutUnit offset) const;
 
-    virtual void expandToEncompassFlowThreadContentsIfNeeded() { };
-
     virtual void repaintFlowThreadContent(const LayoutRect& repaintRect) const;
 
     virtual void collectLayerFragments(LayerFragments&, const LayoutRect&, const LayoutRect&) { }
 
     virtual bool canHaveChildren() const OVERRIDE FINAL { return false; }
     virtual bool canHaveGeneratedChildren() const OVERRIDE FINAL { return true; }
 
     virtual const char* renderName() const OVERRIDE { return "RenderRegion"; }
 
 protected:
@@ skipping 15 matching lines @@
 private:
     LayoutRect m_flowThreadPortionRect;
     bool m_isValid : 1;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderRegion, isRenderRegion());
 
 } // namespace WebCore
 
 #endif // RenderRegion_h