Add SystemTrayObservers

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 194 matching lines @@
         'system/status_area_widget_delegate.cc',
         'system/status_area_widget_delegate.h',
         'system/tray/system_tray.cc',
         'system/tray/system_tray.h',
         'system/tray/system_tray_bubble.cc',
         'system/tray/system_tray_bubble.h',
         'system/tray/system_tray_delegate.cc',
         'system/tray/system_tray_delegate.h',
         'system/tray/system_tray_item.cc',
         'system/tray/system_tray_item.h',
+        'system/tray/system_tray_notifier.cc',
+        'system/tray/system_tray_notifier.h',
         'system/tray/test_system_tray_delegate.cc',
         'system/tray/test_system_tray_delegate.h',
         'system/tray/tray_background_view.cc',
         'system/tray/tray_background_view.h',
         'system/tray/tray_bubble_wrapper.cc',
         'system/tray/tray_bubble_wrapper.h',
         'system/tray/tray_constants.cc',
         'system/tray/tray_constants.h',
         'system/tray/tray_details_view.cc',
         'system/tray/tray_details_view.h',
@@ skipping 479 matching lines @@
             'shell/cocoa/app-Info.plist',
           ],
           'xcode_settings': {
             'INFOPLIST_FILE': 'shell/cocoa/app-Info.plist',
           },
         }],
       ],
     },
   ],
 }