Update rendering classes to use OVERRIDE / FINAL when needed

Source/core/rendering/RenderMediaControlElements.h

 /*
  * Copyright (C) 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Google 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.
@@ skipping 21 matching lines @@
 #include "core/rendering/RenderBlockFlow.h"
 #include "core/rendering/RenderFlexibleBox.h"
 
 namespace WebCore {
 
 class RenderTextTrackContainerElement FINAL : public RenderBlockFlow {
 public:
     RenderTextTrackContainerElement(Element*);
 
 private:
-    virtual void layout();
+    virtual void layout() OVERRIDE;
     virtual bool supportsPartialLayout() const OVERRIDE { return false; }
 };
 
 
 } // namespace WebCore
 
 #endif // RenderMediaControlElements_h