Cast highestEnclosingNodeOfType() return value to tighter type

Source/core/html/HTMLQuoteElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Simon Hausmann <hausmann@kde.org>
  * Copyright (C) 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 23 matching lines @@
     DECLARE_ELEMENT_FACTORY_WITH_TAGNAME(HTMLQuoteElement);
 
 private:
     HTMLQuoteElement(const QualifiedName&, Document&);
 
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
     virtual bool hasLegalLinkAttribute(const QualifiedName&) const OVERRIDE;
     virtual const QualifiedName& subResourceAttributeName() const OVERRIDE;
 };
 
+inline bool isHTMLQuoteElement(const HTMLElement& element)
+{
+    return element.hasTagName(HTMLNames::qTag) || element.hasTagName(HTMLNames::blockquoteTag);
+}
+
+DEFINE_HTMLELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLQuoteElement);
+
 } //namespace
 
 #endif