Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/RenderListBox.h

 /*
  * This file is part of the select element renderer in WebCore.
  *
  * Copyright (C) 2006, 2007, 2009 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
@@ skipping 142 matching lines @@
 
     bool m_optionsChanged;
     bool m_scrollToRevealSelectionAfterLayout;
     bool m_inAutoscroll;
     int m_optionsWidth;
     int m_indexOffset;
 
     RefPtr<Scrollbar> m_vBar;
 };
 
-inline RenderListBox* toRenderListBox(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isListBox());
-    return static_cast<RenderListBox*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderListBox(const RenderListBox*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderListBox, isListBox());
 
 } // namepace WebCore
 
 #endif // RenderListBox_h