Smaller vtbls in RenderObject

Source/core/rendering/RenderFullScreen.cpp

 /*
  * Copyright (C) 2010 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 27 matching lines @@
 
 class RenderFullScreenPlaceholder final : public RenderBlockFlow {
 public:
     RenderFullScreenPlaceholder(RenderFullScreen* owner)
         : RenderBlockFlow(0)
         , m_owner(owner)
     {
         setDocumentForAnonymous(&owner->document());
     }
 private:
-    virtual bool isRenderFullScreenPlaceholder() const override { return true; }
+    virtual bool isOfType(RenderObjectType type) const override { return type == RenderObjectRenderFullScreenPlaceholder || RenderBlockFlow::isOfType(type); }
     virtual void willBeDestroyed() override;
     RenderFullScreen* m_owner;
 };
 
 void RenderFullScreenPlaceholder::willBeDestroyed()
 {
     m_owner->setPlaceholder(0);
     RenderBlockFlow::willBeDestroyed();
 }
 
@@ skipping 146 matching lines @@
     if (!m_placeholder) {
         m_placeholder = new RenderFullScreenPlaceholder(this);
         m_placeholder->setStyle(style);
         if (parent()) {
             parent()->addChild(m_placeholder, this);
             parent()->setNeedsLayoutAndPrefWidthsRecalcAndFullPaintInvalidation();
         }
     } else
         m_placeholder->setStyle(style);
 }