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

Source/core/html/HTMLFormElement.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  *           (C) 2006 Alexey Proskuryakov (ap@nypop.com)
  *
  * 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
@@ skipping 647 matching lines @@
 String HTMLFormElement::method() const
 {
     return FormSubmission::Attributes::methodString(m_attributes.method());
 }
 
 void HTMLFormElement::setMethod(const AtomicString& value)
 {
     setAttribute(methodAttr, value);
 }
 
-String HTMLFormElement::target() const
+AtomicString HTMLFormElement::target() const
 {
     return getAttribute(targetAttr);
 }
 
 bool HTMLFormElement::wasUserSubmitted() const
 {
     return m_wasUserSubmitted;
 }
 
 HTMLFormControlElement* HTMLFormElement::defaultButton() const
@@ skipping 141 matching lines @@
 }
 
 void HTMLFormElement::setDemoted(bool demoted)
 {
     if (demoted)
         UseCounter::count(document(), UseCounter::DemotedFormElement);
     m_wasDemoted = demoted;
 }
 
 } // namespace