Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderMedia.h

 /*
  * Copyright (C) 2007, 2008, 2009, 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 50 matching lines @@
     virtual const char* renderName() const { return "RenderMedia"; }
     virtual bool isMedia() const OVERRIDE FINAL { return true; }
     virtual bool isImage() const OVERRIDE FINAL { return false; }
     virtual void paintReplaced(PaintInfo&, const LayoutPoint&);
 
     virtual bool requiresForcedStyleRecalcPropagation() const OVERRIDE FINAL { return true; }
 
     RenderObjectChildList m_children;
 };
 
-inline RenderMedia* toRenderMedia(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isMedia());
-    return static_cast<RenderMedia*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderMedia(const RenderMedia*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderMedia, isMedia());
 
 } // namespace WebCore
 
 #endif // RenderMedia_h