Smaller vtbls in RenderObject

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 25 matching lines @@
 namespace blink {
 
 struct LayerFragment;
 typedef Vector<LayerFragment, 1> LayerFragments;
 class RenderFlowThread;
 
 class RenderRegion : public RenderBlockFlow {
 public:
     explicit RenderRegion(Element*, RenderFlowThread*);
 
-    virtual bool isRenderRegion() const override final { return true; }
+    virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectRenderRegion || RenderBlockFlow::isOfType(type); }
 
     void setFlowThreadPortionRect(const LayoutRect& rect) { m_flowThreadPortionRect = rect; }
     LayoutRect flowThreadPortionRect() const { return m_flowThreadPortionRect; }
     LayoutRect flowThreadPortionOverflowRect() const;
 
     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; }
@@ skipping 28 matching lines @@
 private:
     LayoutRect m_flowThreadPortionRect;
     bool m_isValid : 1;
 };
 
 DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderRegion, isRenderRegion());
 
 } // namespace blink
 
 #endif // RenderRegion_h