chromeos: Add support for dimming the screen.

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',
   },
 
@@ skipping 213 matching lines @@
         'wm/property_util.h',
         'wm/resize_shadow.cc',
         'wm/resize_shadow.h',
         'wm/resize_shadow_controller.cc',
         'wm/resize_shadow_controller.h',
         'wm/root_window_event_filter.cc',
         'wm/root_window_event_filter.h',
         'wm/root_window_layout_manager.cc',
         'wm/root_window_layout_manager.h',
         'wm/scoped_observer.h',
+        'wm/screen_dimmer.cc',
+        'wm/screen_dimmer.h',
         'wm/shadow.cc',
         'wm/shadow.h',
         'wm/shadow_controller.cc',
         'wm/shadow_controller.h',
         'wm/shadow_types.cc',
         'wm/shadow_types.h',
         'wm/shelf_layout_manager.cc',
         'wm/shelf_layout_manager.h',
         'wm/stacking_controller.cc',
         'wm/stacking_controller.h',
@@ skipping 124 matching lines @@
         'test/test_suite_init.h',
         'test/test_suite_init.mm',
         'tooltips/tooltip_controller_unittest.cc',
         'wm/activation_controller_unittest.cc',
         'wm/base_layout_manager_unittest.cc',
         'wm/frame_painter_unittest.cc',
         'wm/image_grid_unittest.cc',
         'wm/panel_layout_manager_unittest.cc',
         'wm/power_button_controller_unittest.cc',
         'wm/root_window_event_filter_unittest.cc',
+        'wm/screen_dimmer_unittest.cc',
         'wm/shadow_controller_unittest.cc',
         'wm/shelf_layout_manager_unittest.cc',
         'wm/system_gesture_event_filter_unittest.cc',
         'wm/system_modal_container_layout_manager_unittest.cc',
         'wm/toplevel_window_event_filter_unittest.cc',
         'wm/video_detector_unittest.cc',
         'wm/visibility_controller_unittest.cc',
         'wm/window_animations_unittest.cc',
         'wm/window_cycle_controller_unittest.cc',
         'wm/window_modality_controller_unittest.cc',
@@ skipping 126 matching lines @@
             'shell/cocoa/app-Info.plist',
           ],
           'xcode_settings': {
             'INFOPLIST_FILE': 'shell/cocoa/app-Info.plist',
           },
         }],
       ],
     },
   ],
 }