Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGGlyphRefElement.h

 /*
  * Copyright (C) 2011 Leo Yang <leoyang@webkit.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,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
@@ skipping 47 matching lines @@
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGGlyphRefElement)
         DECLARE_ANIMATED_STRING(Href, href)
     END_DECLARE_ANIMATED_PROPERTIES
 
     float m_x;
     float m_y;
     float m_dx;
     float m_dy;
 };
 
-inline SVGGlyphRefElement* toSVGGlyphRefElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(SVGNames::glyphRefTag));
-    return static_cast<SVGGlyphRefElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGGlyphRefElement, hasTagName(SVGNames::glyphRefTag));
 
 }
 
 #endif
 #endif