Make sure getAttribute() / setAttribute() callers use AtomicStrings

Source/core/html/HTMLTableElement.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, 2008 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 44 matching lines @@
     void deleteTFoot();
     PassRefPtr<HTMLElement> createTBody();
     PassRefPtr<HTMLElement> createCaption();
     void deleteCaption();
     PassRefPtr<HTMLElement> insertRow(int index, ExceptionState&);
     void deleteRow(int index, ExceptionState&);
 
     PassRefPtr<HTMLCollection> rows();
     PassRefPtr<HTMLCollection> tBodies();
 
-    String rules() const;
-    String summary() const;
+    const AtomicString& rules() const;
+    const AtomicString& summary() const;
 
     const StylePropertySet* additionalCellStyle();
     const StylePropertySet* additionalGroupStyle(bool rows);
 
 private:
     explicit HTMLTableElement(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;
@@ skipping 31 matching lines @@
 inline bool isHTMLTableElement(const Element* element)
 {
     return element->hasTagName(HTMLNames::tableTag);
 }
 
 DEFINE_NODE_TYPE_CASTS(HTMLTableElement, hasTagName(HTMLNames::tableTag));
 
 } //namespace
 
 #endif