Update a11y of volume row in CrOS system menu.

ash/common/system/chromeos/audio/volume_view.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 ASH_COMMON_SYSTEM_CHROMEOS_AUDIO_VOLUME_VIEW_H_
 #define ASH_COMMON_SYSTEM_CHROMEOS_AUDIO_VOLUME_VIEW_H_
 
 #include "base/macros.h"
 #include "ui/views/controls/button/button.h"
 #include "ui/views/controls/slider.h"
 #include "ui/views/view.h"
 
 namespace views {
 class CustomButton;
 class ImageView;
-class Separator;
 class Slider;
 }
 
 namespace ash {
 class SystemTrayItem;
 class TriView;
 
 namespace system {
 class TrayAudioDelegate;
 }
@@ skipping 24 matching lines @@
 
   // SliderListener:
   void SliderValueChanged(views::Slider* sender,
                           float value,
                           float old_value,
                           views::SliderChangeReason reason) override;
 
   // views::ButtonListener:
   void ButtonPressed(views::Button* sender, const ui::Event& event) override;
 
-  // views::View:
-  bool OnKeyPressed(const ui::KeyEvent& event) override;
-  void OnBoundsChanged(const gfx::Rect& previous_bounds) override;
-
   SystemTrayItem* owner_;
   // The only immediate child view of |this|. All other view elements are added
   // to the |tri_view_| to handle layout.
   TriView* tri_view_;
   system::TrayAudioDelegate* audio_delegate_;
   views::CustomButton* more_button_;
   VolumeButton* icon_;
   views::Slider* slider_;
-  views::Separator* separator_;  // Not used in material design.
   views::ImageView* device_type_;
   bool is_default_view_;
 
   DISALLOW_COPY_AND_ASSIGN(VolumeView);
 };
 
 }  // namespace tray
 }  // namespace ash
 
 #endif  // ASH_COMMON_SYSTEM_CHROMEOS_AUDIO_VOLUME_VIEW_H_