Make calls to AtomicString(const String&) explicit in web/

Source/core/html/HTMLFormElement.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 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 72 matching lines @@
     String name() const;
 
     bool noValidate() const;
 
     const AtomicString& action() const;
     void setAction(const AtomicString&);
 
     String method() const;
     void setMethod(const AtomicString&);
 
-    virtual String target() const;
+    virtual AtomicString target() const OVERRIDE;
 
     bool wasUserSubmitted() const;
 
     HTMLFormControlElement* defaultButton() const;
 
     bool checkValidity();
     bool checkValidityWithoutDispatchingEvents();
 
     enum AutocompleteResult {
         AutocompleteResultSuccess,
@@ skipping 77 matching lines @@
 
     Vector<RefPtr<Event> > m_pendingAutocompleteEvents;
     Timer<HTMLFormElement> m_requestAutocompleteTimer;
 };
 
 DEFINE_NODE_TYPE_CASTS(HTMLFormElement, hasTagName(HTMLNames::formTag));
 
 } // namespace WebCore
 
 #endif // HTMLFormElement_h