Replace elementHasLegalLinkAttribute() helper with virtual function

Source/core/html/HTMLTableCellElement.cpp

 /*
  * 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 110 matching lines @@
     if (HTMLTableElement* table = findParentTable())
         return table->additionalCellStyle();
     return 0;
 }
 
 bool HTMLTableCellElement::isURLAttribute(const Attribute& attribute) const
 {
     return attribute.name() == backgroundAttr || HTMLTablePartElement::isURLAttribute(attribute);
 }
 
+bool HTMLTableCellElement::hasLegalLinkAttribute(const QualifiedName& name) const
+{
+    return (hasLocalName(tdTag) && name == backgroundAttr) || HTMLTablePartElement::hasLegalLinkAttribute(name);
+}
+
 const AtomicString& HTMLTableCellElement::abbr() const
 {
     return fastGetAttribute(abbrAttr);
 }
 
 const AtomicString& HTMLTableCellElement::axis() const
 {
     return fastGetAttribute(axisAttr);
 }
 
@@ skipping 27 matching lines @@
 
     RenderTableCell* tableCellRenderer = toRenderTableCell(cellRenderer);
     RenderTableCell* cellAboveRenderer = tableCellRenderer->table()->cellAbove(tableCellRenderer);
     if (!cellAboveRenderer)
         return 0;
 
     return toHTMLTableCellElement(cellAboveRenderer->node());
 }
 
 } // namespace WebCore