Clean up static_cast<SVGFooElement*> by using toSVGFoo()

Source/core/svg/SVGAltGlyphElement.h

 /*
  * Copyright (C) 2004, 2005, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2008 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.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #ifndef SVGAltGlyphElement_h
 #define SVGAltGlyphElement_h
 
 #if ENABLE(SVG_FONTS)
+#include "SVGNames.h"
 #include "core/svg/SVGTextPositioningElement.h"
 #include "core/svg/SVGURIReference.h"
 #include "wtf/Vector.h"
 
 namespace WebCore {
 
 class ExceptionState;
 class SVGGlyphElement;
 
 class SVGAltGlyphElement FINAL : public SVGTextPositioningElement,
@@ skipping 12 matching lines @@
     explicit SVGAltGlyphElement(Document&);
 
     virtual RenderObject* createRenderer(RenderStyle*);
     virtual bool childShouldCreateRenderer(const Node& child) const;
 
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGAltGlyphElement)
         DECLARE_ANIMATED_STRING(Href, href)
     END_DECLARE_ANIMATED_PROPERTIES
 };
 
+DEFINE_NODE_TYPE_CASTS(SVGAltGlyphElement, hasTagName(SVGNames::altGlyphTag));
+
 } // namespace WebCore
 
 #endif
 #endif