Revert "Remove webkit_glue::BuildUserAgent(), change the contract in webkit_glue"

content/renderer/renderer_glue.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 // This file provides the embedder's side of random webkit glue functions.
 
 #include "build/build_config.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
@@ skipping 229 matching lines @@
 #endif
 
 string16 GetLocalizedString(int message_id) {
   return content::GetContentClient()->GetLocalizedString(message_id);
 }
 
 base::StringPiece GetDataResource(int resource_id) {
   return content::GetContentClient()->GetDataResource(resource_id);
 }
 
+std::string BuildUserAgent(bool mimic_windows) {
+  return content::GetContentClient()->GetUserAgent(mimic_windows);
+}
+
 }  // namespace webkit_glue