Fix user agent override restore pipeline

content/public/browser/web_contents_observer.h

 // 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.
 
 #ifndef CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 #define CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_
 
 #include "base/process_util.h"
 #include "content/common/content_export.h"
 #include "content/public/browser/navigation_controller.h"
@@ skipping 108 matching lines @@
   // it's used for anything in case there's an exploited renderer.
   virtual void PluginHungStatusChanged(int plugin_child_id,
                                        const FilePath& plugin_path,
                                        bool is_hung) {}
 
   // Invoked when the WebContents is being destroyed. Gives subclasses a chance
   // to cleanup. At the time this is invoked |web_contents()| returns NULL.
   // It is safe to delete 'this' from here.
   virtual void WebContentsDestroyed(WebContents* web_contents) {}
 
+  // Called when the user agent override for a WebContents has been changed.
+  virtual void UserAgentOverrideSet(const std::string& user_agent) {}
+
   // IPC::Listener implementation.
   virtual bool OnMessageReceived(const IPC::Message& message) OVERRIDE;
 
   // IPC::Sender implementation.
   virtual bool Send(IPC::Message* message) OVERRIDE;
   int routing_id() const;
 
  protected:
   // Use this constructor when the object is tied to a single WebContents for
   // its entire lifetime.
@@ skipping 19 matching lines @@
   void WebContentsImplDestroyed();
 
   WebContentsImpl* web_contents_;
 
   DISALLOW_COPY_AND_ASSIGN(WebContentsObserver);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_PUBLIC_BROWSER_WEB_CONTENTS_OBSERVER_H_