Apply FINAL to the RenderObject hierarchy.

Source/core/rendering/RenderButton.h

 /*
  * Copyright (C) 2005 Apple Computer
  *
  * 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
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 14 matching lines @@
 #include "Timer.h"
 #include <wtf/OwnPtr.h>
 
 namespace WebCore {
 
 class RenderTextFragment;
 
 // RenderButtons are just like normal flexboxes except that they will generate an anonymous block child.
 // For inputs, they will also generate an anonymous RenderText and keep its style and content up
 // to date as the button changes.
-class RenderButton : public RenderFlexibleBox {
+class RenderButton FINAL : public RenderFlexibleBox {
 public:
     explicit RenderButton(Element*);
     virtual ~RenderButton();
 
     virtual const char* renderName() const { return "RenderButton"; }
     virtual bool isRenderButton() const { return true; }
 
     virtual bool canBeSelectionLeaf() const OVERRIDE { return node() && node()->rendererIsEditable(); }
 
     virtual void addChild(RenderObject* newChild, RenderObject *beforeChild = 0);
@@ skipping 39 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isRenderButton());
     return static_cast<const RenderButton*>(object);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toRenderButton(const RenderButton*);
 
 } // namespace WebCore
 
 #endif // RenderButton_h