Use DEFINE_NODE_TYPE_CASTS instead of using manual toSVGFooElement()

Source/core/svg/SVGFEDiffuseLightingElement.h

 /*
  * Copyright (C) 2004, 2005, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Oliver Hunt <oliver@nerget.com>
  *
  * 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 39 matching lines @@
 
     BEGIN_DECLARE_ANIMATED_PROPERTIES(SVGFEDiffuseLightingElement)
         DECLARE_ANIMATED_STRING(In1, in1)
         DECLARE_ANIMATED_NUMBER(DiffuseConstant, diffuseConstant)
         DECLARE_ANIMATED_NUMBER(SurfaceScale, surfaceScale)
         DECLARE_ANIMATED_NUMBER(KernelUnitLengthX, kernelUnitLengthX)
         DECLARE_ANIMATED_NUMBER(KernelUnitLengthY, kernelUnitLengthY)
     END_DECLARE_ANIMATED_PROPERTIES
 };
 
-inline SVGFEDiffuseLightingElement* toSVGFEDiffuseLightingElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(SVGNames::feDiffuseLightingTag));
-    return static_cast<SVGFEDiffuseLightingElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(SVGFEDiffuseLightingElement, hasTagName(SVGNames::feDiffuseLightingTag));
 
 } // namespace WebCore
 
 #endif