Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderFrameSet.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 2006, 2008 Apple Inc. All rights reserved.
  *
  * 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.
  *
@@ skipping 114 matching lines @@
 
     RenderObjectChildList m_children;
 
     GridAxis m_rows;
     GridAxis m_cols;
 
     bool m_isResizing;
     bool m_isChildResizing;
 };
 
-
-inline RenderFrameSet* toRenderFrameSet(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isFrameSet());
-    return static_cast<RenderFrameSet*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderFrameSet(const RenderFrameSet*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderFrameSet, isFrameSet());
 
 } // namespace WebCore
 
 #endif // RenderFrameSet_h