Use mojo volume interfaces for mash and classic ash.

ash/common/system/volume_control_delegate.h

Index: ash/common/system/volume_control_delegate.h
diff --git a/ash/common/system/volume_control_delegate.h b/ash/common/system/volume_control_delegate.h
deleted file mode 100644
index 9d292c9a19f2382dfd0c12d5fc7777c615e85a58..0000000000000000000000000000000000000000
--- a/ash/common/system/volume_control_delegate.h
+++ /dev/null
@@ -1,26 +0,0 @@
-// 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 ASH_COMMON_SYSTEM_VOLUME_CONTROL_DELEGATE_H_
-#define ASH_COMMON_SYSTEM_VOLUME_CONTROL_DELEGATE_H_
-
-namespace ui {
-class Accelerator;
-}  // namespace ui
-
-namespace ash {
-
-// Delegate for controlling the volume.
-class VolumeControlDelegate {
- public:
-  virtual ~VolumeControlDelegate() {}
-
-  virtual void HandleVolumeMute(const ui::Accelerator& accelerator) = 0;
-  virtual void HandleVolumeDown(const ui::Accelerator& accelerator) = 0;
-  virtual void HandleVolumeUp(const ui::Accelerator& accelerator) = 0;
-};
-
-}  // namespace ash
-
-#endif  // ASH_COMMON_SYSTEM_VOLUME_CONTROL_DELEGATE_H_