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

Source/web/WebViewImpl.cpp

 /*
  * Copyright (C) 2011, 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Redistributions in binary form must reproduce the above
@@ skipping 2450 matching lines @@
     return m_page->mainFrame()->document()->encodingName();
 }
 
 void WebViewImpl::setPageEncoding(const WebString& encodingName)
 {
     if (!m_page)
         return;
 
     // Only change override encoding, don't change default encoding.
     // Note that the new encoding must be 0 if it isn't supposed to be set.
-    String newEncodingName;
+    AtomicString newEncodingName;
     if (!encodingName.isEmpty())
         newEncodingName = encodingName;
     m_page->mainFrame()->loader().reload(NormalReload, KURL(), newEncodingName);
 }
 
 bool WebViewImpl::dispatchBeforeUnloadEvent()
 {
     // FIXME: This should really cause a recursive depth-first walk of all
     // frames in the tree, calling each frame's onbeforeunload.  At the moment,
     // we're consistent with Safari 3.1, not IE/FF.
@@ skipping 1531 matching lines @@
     const PageScaleConstraints& constraints = m_pageScaleConstraintsSet.pageDefinedConstraints();
 
     if (!mainFrameImpl() || !mainFrameImpl()->frameView())
         return false;
 
     return mainFrameImpl()->frameView()->layoutSize().width() == m_size.width
         || (constraints.minimumScale == constraints.maximumScale && constraints.minimumScale != -1);
 }
 
 } // namespace blink