Use DEFINE_NODE_TYPE_CASTS instead of using manual toHTMLFooElement()

Source/core/html/HTMLMetaElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2010 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 49 matching lines @@
     float parseViewportValueAsZoom(const String& key, const String& value);
     float parseViewportValueAsUserZoom(const String& key, const String& value);
     float parseViewportValueAsDPI(const String& key, const String& value);
 
     void reportViewportWarning(ViewportErrorCode, const String& replacement1, const String& replacement2);
 
     void process();
     void processViewportContentAttribute(const String& content, ViewportDescription::Type origin);
 };
 
-inline HTMLMetaElement* toHTMLMetaElement(Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(HTMLNames::metaTag));
-    return static_cast<HTMLMetaElement*>(node);
-}
-
-inline const HTMLMetaElement* toHTMLMetaElement(const Node* node)
-{
-    ASSERT_WITH_SECURITY_IMPLICATION(!node || node->hasTagName(HTMLNames::metaTag));
-    return static_cast<const HTMLMetaElement*>(node);
-}
+DEFINE_NODE_TYPE_CASTS(HTMLMetaElement, hasTagName(HTMLNames::metaTag));
 
 } // namespace WebCore
 
 #endif