Allow override of user agent depending on url.

content/public/renderer/content_renderer_client.cc

 // Copyright (c) 2012 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/public/renderer/content_renderer_client.h"
 
 namespace content {
 
 SkBitmap* ContentRendererClient::GetSadPluginBitmap() {
   return NULL;
@@ skipping 178 matching lines @@
 bool ContentRendererClient::IsPluginAllowedToUseDevChannelAPIs() {
   return false;
 }
 
 BrowserPluginDelegate* ContentRendererClient::CreateBrowserPluginDelegate(
     RenderFrame* render_frame,
     const std::string& mime_type) {
   return NULL;
 }
 
+std::string ContentRendererClient::GetUserAgentOverrideForURL(const GURL& url) {
+  return std::string();
+}
+
 }  // namespace content