Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGUseElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006, 2007 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 108 matching lines @@
     virtual Timer<SVGElement>* svgLoadEventTimer() OVERRIDE { return &m_svgLoadEventTimer; }
 
     bool m_wasInsertedByParser;
     bool m_haveFiredLoadEvent;
     bool m_needsShadowTreeRecreation;
     RefPtr<SVGElementInstance> m_targetElementInstance;
     ResourcePtr<DocumentResource> m_resource;
     Timer<SVGElement> m_svgLoadEventTimer;
 };
 
-inline SVGUseElement* toSVGUseElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(SVGNames::useTag));
-    return static_cast<SVGUseElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGUseElement, hasTagName(SVGNames::useTag));
 
 }
 
 #endif