Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGElement.h

 /*
  * Copyright (C) 2004, 2005, 2006, 2008 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005, 2006 Rob Buis <buis@kde.org>
  * Copyright (C) 2009 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.
  *
@@ skipping 189 matching lines @@
     {
         if (key.hasPrefix()) {
             QualifiedNameComponents components = { nullAtom.impl(), key.localName().impl(), key.namespaceURI().impl() };
             return hashComponents(components);
         }
         return DefaultHash<QualifiedName>::Hash::hash(key);
     }
     static bool equal(const QualifiedName& a, const QualifiedName& b) { return a.matches(b); }
 };
 
-inline SVGElement* toSVGElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isSVGElement());
-    return static_cast<SVGElement*>(node);
-}
-
-inline const SVGElement* toSVGElement(const Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->isSVGElement());
-    return static_cast<const SVGElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGElement, isSVGElement());
 
 }
 
 #endif