Refactor AccelerometerReader to provide an Observer

athena/system/orientation_controller.h

 // Copyright 2014 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 ATHENA_SYSTEM_ORIENTATION_CONTROLLER_H_
 #define ATHENA_SYSTEM_ORIENTATION_CONTROLLER_H_
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "chromeos/accelerometer/accelerometer_reader.h"
 #include "ui/gfx/display.h"
 
 namespace base {
 class TaskRunner;
 }
 
 namespace athena {
 
 // Monitors accelerometers, detecting orientation changes. When a change is
 // detected rotates the root window to match.
-class OrientationController
-    : public chromeos::AccelerometerReader::Delegate {
+class OrientationController : public chromeos::AccelerometerReader::Observer {
  public:
   OrientationController();
   ~OrientationController() override;
 
   void InitWith(scoped_refptr<base::TaskRunner> blocking_task_runner);
   void Shutdown();
 
-  // chromeos::AccelerometerReader::Delegate
-  virtual void HandleAccelerometerUpdate(
-      const ui::AccelerometerUpdate& update) override;
+  // chromeos::AccelerometerReader::Observer:
+  void OnAccelerometerUpdated(const ui::AccelerometerUpdate& update) override;
 
  private:
   // The last configured rotation.
   gfx::Display::Rotation current_rotation_;
 
   scoped_ptr<chromeos::AccelerometerReader> accelerometer_reader_;
 
   DISALLOW_COPY_AND_ASSIGN(OrientationController);
 };
 
 }  // namespace athena
 
 #endif  // ATHENA_SYSTEM_ORIENTATION_CONTROLLER_H_