Intorduce PowerButtonObserver API

athena/athena.gyp

 # 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.
 
 {
   'variables': {
     'chromium_code': 1,
   },
   'targets': [
     {
@@ skipping 51 matching lines @@
         'home/home_card_gesture_manager.h',
         'home/home_card_impl.cc',
         'home/minimized_home.cc',
         'home/minimized_home.h',
         'home/public/app_model_builder.h',
         'home/public/home_card.h',
         'home/public/search_controller_factory.h',
         'input/accelerator_manager_impl.cc',
         'input/accelerator_manager_impl.h',
         'input/input_manager_impl.cc',
+        'input/input_manager_impl.h',
         'input/public/accelerator_manager.h',
         'input/public/input_manager.h',
         'resource_manager/delegate/resource_manager_delegate.cc',
         'resource_manager/memory_pressure_notifier.cc',
         'resource_manager/memory_pressure_notifier.h',
         'resource_manager/public/resource_manager.h',
         'resource_manager/public/resource_manager_delegate.h',
         'resource_manager/resource_manager_impl.cc',
         'screen/public/screen_manager.h',
         'screen/screen_accelerator_handler.cc',
@@ skipping 200 matching lines @@
         'resources/athena_resources.gyp:athena_pak',
       ],
       'sources': [
         'activity/activity_manager_unittest.cc',
         'content/app_activity_unittest.cc',
         'env/athena_env_unittest.cc',
         'home/athena_start_page_view_unittest.cc',
         'home/home_card_gesture_manager_unittest.cc',
         'home/home_card_unittest.cc',
         'input/accelerator_manager_unittest.cc',
+        'input/input_manager_unittest.cc',
         'resource_manager/memory_pressure_notifier_unittest.cc',
         'resource_manager/resource_manager_unittest.cc',
         'screen/screen_manager_unittest.cc',
         'test/base/athena_unittests.cc',
         'util/drag_handle_unittest.cc',
         'util/fill_layout_manager_unittest.cc',
         'wm/split_view_controller_unittest.cc',
         'wm/window_list_provider_impl_unittest.cc',
         'wm/window_manager_unittest.cc',
       ],
     }
   ],
 }