Clean up toHTMLFooElement() using DEFINE_NODE_TYPE_CASTS_WITH_FUNCTION

Source/core/html/HTMLAreaElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2008, 2009, 2011 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 60 matching lines @@
 inline bool isHTMLAreaElement(const Node* node)
 {
     return node->hasTagName(HTMLNames::areaTag);
 }
 
 inline bool isHTMLAreaElement(const Element* element)
 {
     return element->hasTagName(HTMLNames::areaTag);
 }
 
-inline HTMLAreaElement* toHTMLAreaElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || isHTMLAreaElement(node));
-    return static_cast<HTMLAreaElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(HTMLAreaElement, hasTagName(HTMLNames::areaTag));
 
 } //namespace
 
 #endif