Refactors DeviceOrientation to make it more extensible

content/browser/device_orientation/orientation_message_filter.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_BROWSER_DEVICE_ORIENTATION_ORIENTATION_MESSAGE_FILTER_H_
 #define CONTENT_BROWSER_DEVICE_ORIENTATION_ORIENTATION_MESSAGE_FILTER_H_
 
 #include <map>
 
-#include "content/browser/device_orientation/provider.h"
-#include "content/public/browser/browser_message_filter.h"
+#include "content/browser/device_orientation/message_filter.h"
 
 namespace device_orientation {
 
-class OrientationMessageFilter : public content::BrowserMessageFilter {
+class OrientationMessageFilter : public MessageFilter {
  public:
   OrientationMessageFilter();
 
   // content::BrowserMessageFilter implementation.
   virtual bool OnMessageReceived(const IPC::Message& message,
                                  bool* message_was_ok) OVERRIDE;
 
  private:
   virtual ~OrientationMessageFilter();
 
-  void OnStartUpdating(int render_view_id);
-  void OnStopUpdating(int render_view_id);
-
-  // Helper class that observes a Provider and forwards updates to a RenderView.
-  class ObserverDelegate;
-
-  // map from render_view_id to ObserverDelegate.
-  std::map<int, scoped_refptr<ObserverDelegate> > observers_map_;
-
-  scoped_refptr<Provider> provider_;
-
   DISALLOW_COPY_AND_ASSIGN(OrientationMessageFilter);
 };
 
 }  // namespace device_orientation
 
 #endif  // CONTENT_BROWSER_DEVICE_ORIENTATION_ORIENTATION_MESSAGE_FILTER_H_