Replace elementHasLegalLinkAttribute() helper with virtual function

Source/core/html/HTMLTableCellElement.h

 /*
  * Copyright (C) 1997 Martin Jones (mjones@kde.org)
  *           (C) 1997 Torben Weis (weis@kde.org)
  *           (C) 1998 Waldo Bastian (bastian@kde.org)
  *           (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2003, 2004, 2005, 2006, 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
@@ skipping 41 matching lines @@
 
 private:
     HTMLTableCellElement(const QualifiedName&, Document&);
 
     virtual void parseAttribute(const QualifiedName&, const AtomicString&) OVERRIDE;
     virtual bool isPresentationAttribute(const QualifiedName&) const OVERRIDE;
     virtual void collectStyleForPresentationAttribute(const QualifiedName&, const AtomicString&, MutableStylePropertySet*) OVERRIDE;
     virtual const StylePropertySet* additionalPresentationAttributeStyle() OVERRIDE;
 
     virtual bool isURLAttribute(const Attribute&) const OVERRIDE;
+    virtual bool hasLegalLinkAttribute(const QualifiedName&) const OVERRIDE;
 };
 
 inline bool isHTMLTableCellElement(const Node& node)
 {
     return node.hasTagName(HTMLNames::tdTag) || node.hasTagName(HTMLNames::thTag);
 }
 
 DEFINE_ELEMENT_TYPE_CASTS_WITH_FUNCTION(HTMLTableCellElement);
 
 } // namespace
 
 #endif