Introduce DEFINE_RENDER_OBJECT_TYPE_CASTS to replace manual toRenderFoo, and use it

Source/core/rendering/svg/RenderSVGContainer.h

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2007 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 Google, Inc.  All rights reserved.
  * Copyright (C) 2009 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 69 matching lines @@
 
 private:
     RenderObjectChildList m_children;
     FloatRect m_objectBoundingBox;
     bool m_objectBoundingBoxValid;
     FloatRect m_strokeBoundingBox;
     FloatRect m_repaintBoundingBox;
     bool m_needsBoundariesUpdate : 1;
 };
 
-inline RenderSVGContainer* toRenderSVGContainer(RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isSVGContainer());
-    return static_cast<RenderSVGContainer*>(object);
-}
-
-inline const RenderSVGContainer* toRenderSVGContainer(const RenderObject* object)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!object || object->isSVGContainer());
-    return static_cast<const RenderSVGContainer*>(object);
-}
-
-// This will catch anyone doing an unnecessary cast.
-void toRenderSVGContainer(const RenderSVGContainer*);
+DEFINE_RENDER_OBJECT_TYPE_CASTS(RenderSVGContainer, isSVGContainer());
 
 } // namespace WebCore
 
 #endif // RenderSVGContainer_h