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

Source/core/html/HTMLDocument.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  * Copyright (C) 2004, 2006, 2007, 2008, 2009 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 @@
 class HTMLElement;
 
 class HTMLDocument : public Document, public ResourceClient {
 public:
     static PassRefPtr<HTMLDocument> create(const DocumentInit& initializer = DocumentInit())
     {
         return adoptRef(new HTMLDocument(initializer));
     }
     virtual ~HTMLDocument();
 
-    String dir();
-    void setDir(const String&);
+    const AtomicString& dir();
+    void setDir(const AtomicString&);
 
     String designMode() const;
     void setDesignMode(const String&);
 
     Element* activeElement();
     bool hasFocus();
 
     const AtomicString& bgColor() const;
     void setBgColor(const AtomicString&);
     const AtomicString& fgColor() const;
@@ skipping 76 matching lines @@
     ASSERT_WITH_SECURITY_IMPLICATION(document.isHTMLDocument());
     return static_cast<const HTMLDocument&>(document);
 }
 
 // This will catch anyone doing an unnecessary cast.
 void toHTMLDocument(const HTMLDocument*);
 
 } // namespace WebCore
 
 #endif // HTMLDocument_h