Move ash tray audio UI code from ash/system/audio to ash/system/chromeos/audio.

ash/ash.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
   },
   'includes': [
@@ skipping 157 matching lines @@
         'shelf/shelf_layout_manager.cc',
         'shelf/shelf_layout_manager.h',
         'shelf/shelf_types.h',
         'shelf/shelf_widget.cc',
         'shelf/shelf_widget.h',
         'shell.cc',
         'shell.h',
         'shell_delegate.h',
         'shell_factory.h',
         'shell_window_ids.h',
-        'system/audio/audio_observer.h',
-        'system/audio/tray_volume.cc',
-        'system/audio/tray_volume.h',
         'system/bluetooth/bluetooth_observer.h',
         'system/bluetooth/tray_bluetooth.cc',
         'system/bluetooth/tray_bluetooth.h',
         'system/brightness/brightness_observer.h',
         'system/brightness/brightness_control_delegate.h',
         'system/brightness/tray_brightness.cc',
         'system/brightness/tray_brightness.h',
+        'system/chromeos/audio/audio_observer.h',
+        'system/chromeos/audio/tray_volume.cc',
+        'system/chromeos/audio/tray_volume.h',        
         'system/chromeos/enterprise/enterprise_domain_observer.h',
         'system/chromeos/enterprise/tray_enterprise.h',
         'system/chromeos/enterprise/tray_enterprise.cc',
         'system/chromeos/keyboard_brightness_controller.cc',
         'system/chromeos/keyboard_brightness_controller.h',
         'system/chromeos/network/network_detailed_view.h',
         'system/chromeos/network/network_icon.cc',
         'system/chromeos/network/network_icon.h',
         'system/chromeos/network/network_icon_animation.cc',
         'system/chromeos/network/network_icon_animation.h',
@@ skipping 627 matching lines @@
             'shell/cocoa/app-Info.plist',
           ],
           'xcode_settings': {
             'INFOPLIST_FILE': 'shell/cocoa/app-Info.plist',
           },
         }],
       ],
     },
   ],
 }