mash: Introduce WmSystemTrayNotifier for //ash/common

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,
     # These files lists are shared with the GN build.
     'ash_sources': [
       'accelerators/accelerator_commands.cc',
@@ skipping 85 matching lines @@
       'common/system/networking_config_delegate.cc',
       'common/system/networking_config_delegate.h',
       'common/system/tray/default_system_tray_delegate.cc',
       'common/system/tray/default_system_tray_delegate.h',
       'common/system/tray/fixed_sized_image_view.cc',
       'common/system/tray/fixed_sized_image_view.h',
       'common/system/tray/system_tray_delegate.cc',
       'common/system/tray/system_tray_delegate.h',
       'common/system/tray/tray_constants.cc',
       'common/system/tray/tray_constants.h',
+      'common/system/tray/wm_system_tray_notifier.cc',
+      'common/system/tray/wm_system_tray_notifier.h',
       'common/system/update/update_observer.h',
       'common/system/volume_control_delegate.h',
       'common/wm/always_on_top_controller.cc',
       'common/wm/always_on_top_controller.h',
       'common/wm/background_animator.cc',
       'common/wm/background_animator.h',
       'common/wm/container_finder.cc',
       'common/wm/container_finder.h',
       'common/wm/default_state.cc',
       'common/wm/default_state.h',
@@ skipping 1333 matching lines @@
                   '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
                 ],
               }
             ],
           ],
         },
       ],
     }],
   ],
 }