Consolidate volume control code.

chrome/browser/ui/ash/volume_controller_chromeos.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 CHROME_BROWSER_UI_ASH_VOLUME_CONTROLLER_CHROMEOS_H_
 #define CHROME_BROWSER_UI_ASH_VOLUME_CONTROLLER_CHROMEOS_H_
 
 #include "ash/volume_control_delegate.h"
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 
 // A class which controls volume when F8-10 or a multimedia key for volume is
 // pressed.
 class VolumeController : public ash::VolumeControlDelegate {
  public:
   VolumeController() {}
   virtual ~VolumeController() {}
 
   // Overridden from ash::VolumeControlDelegate:
   virtual bool HandleVolumeMute(const ui::Accelerator& accelerator) OVERRIDE;
   virtual bool HandleVolumeDown(const ui::Accelerator& accelerator) OVERRIDE;
   virtual bool HandleVolumeUp(const ui::Accelerator& accelerator) OVERRIDE;
+  virtual bool IsAudioMuted() const OVERRIDE;
+  virtual void SetAudioMuted(bool muted) OVERRIDE;
+  virtual float GetVolumeLevel() const OVERRIDE;
+  virtual void SetVolumeLevel(float level) OVERRIDE;
   virtual void SetVolumePercent(double percent) OVERRIDE;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(VolumeController);
 };
 
 #endif  // CHROME_BROWSER_UI_ASH_VOLUME_CONTROLLER_CHROMEOS_H_