Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGClipPathElement.h

 /*
  * Copyright (C) 2004, 2005, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  *
  * 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.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 38 matching lines @@
     virtual void childrenChanged(bool changedByParser = false, Node* beforeChange = 0, Node* afterChange = 0, int childCountDelta = 0);
 
     virtual RenderObject* createRenderer(RenderStyle*);
 
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGClipPathElement)
         DECLARE_ANIMATED_ENUMERATION(ClipPathUnits, clipPathUnits, SVGUnitTypes::SVGUnitType)
         DECLARE_ANIMATED_BOOLEAN(ExternalResourcesRequired, externalResourcesRequired)
     END_DECLARE_ANIMATED_PROPERTIES
 };
 
-inline SVGClipPathElement* toSVGClipPathElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(SVGNames::clipPathTag));
-    return static_cast<SVGClipPathElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGClipPathElement, hasTagName(SVGNames::clipPathTag));
 
 }
 
 #endif