Remove dependency on PrefChangeRegistrar and renderer_preferences_util from content.

content/browser/renderer_host/render_view_host_observer.h

 // 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.
 
 #ifndef CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
 #define CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_
 
 #include "ipc/ipc_channel.h"
 
 class RenderViewHost;
+struct ViewMsg_Navigate_Params;
 
 // An observer API implemented by classes which want to filter IPC messages from
 // RenderViewHost.
 class RenderViewHostObserver : public IPC::Channel::Listener,
                                public IPC::Message::Sender {
  public:
 
  protected:
   explicit RenderViewHostObserver(RenderViewHost* render_view_host);
 
   virtual ~RenderViewHostObserver();
 
   // Invoked after the RenderViewHost is created in the renderer process.  After
   // this point, messages can be sent to it (or to observers in the renderer).
   virtual void RenderViewHostInitialized();
 
   // Invoked when the RenderViewHost is being destroyed. Gives subclasses a
   // chance to cleanup.  The base implementation will delete the object.
   virtual void RenderViewHostDestroyed();
 
+  // Notifies that a navigation is starting.
+  virtual void Navigate(const ViewMsg_Navigate_Params& params);
+
   // IPC::Channel::Listener implementation.
   virtual bool OnMessageReceived(const IPC::Message& message);
 
   // IPC::Message::Sender implementation.
   virtual bool Send(IPC::Message* message);
 
   RenderViewHost* render_view_host() const { return render_view_host_; }
   int routing_id() { return routing_id_; }
 
  private:
   friend class RenderViewHost;
 
   // Invoked from RenderViewHost. Invokes RenderViewHostDestroyed and NULL out
   // |render_view_host_|.
   void RenderViewHostDestruction();
 
   RenderViewHost* render_view_host_;
 
   // The routing ID of the associated RenderViewHost.
   int routing_id_;
 
   DISALLOW_COPY_AND_ASSIGN(RenderViewHostObserver);
 };
 
 #endif  // CONTENT_BROWSER_RENDERER_HOST_RENDER_VIEW_HOST_OBSERVER_H_