Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGPathElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 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 112 matching lines @@
     virtual void removedFrom(ContainerNode*) OVERRIDE;
 
     void invalidateMPathDependencies();
 
 private:
     OwnPtr<SVGPathByteStream> m_pathByteStream;
     mutable SVGSynchronizableAnimatedProperty<SVGPathSegList> m_pathSegList;
     bool m_isAnimValObserved;
 };
 
-inline SVGPathElement* toSVGPathElement(Element* element)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!element || element->hasTagName(SVGNames::pathTag));
-    return static_cast<SVGPathElement*>(element);
-}
+DEFINE_NODE_TYPE_CASTS(SVGPathElement, hasTagName(SVGNames::pathTag));
 
 } // namespace WebCore
 
 #endif