use the userAgent() in the same loadable module as RendererWebKitPlatformSupportImpl

content/renderer/renderer_webkitplatformsupport_impl.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.
 
 #include "content/renderer/renderer_webkitplatformsupport_impl.h"
 
 #include "base/command_line.h"
 #include "base/file_path.h"
 #include "base/file_util.h"
 #include "base/platform_file.h"
@@ skipping 590 matching lines @@
 
 //------------------------------------------------------------------------------
 
 WebBlobRegistry* RendererWebKitPlatformSupportImpl::blobRegistry() {
   // ChildThread::current can be NULL when running some tests.
   if (!blob_registry_.get() && ChildThread::current()) {
     blob_registry_.reset(new WebBlobRegistryImpl(ChildThread::current()));
   }
   return blob_registry_.get();
 }
+
+WebKit::WebString RendererWebKitPlatformSupportImpl::userAgent(
+    const WebKit::WebURL& url) {
+ return WebKitPlatformSupportImpl::userAgent(url);
+}
+