[CrOS] Initial rough cut of alt-tab window cycling UI.

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 655 matching lines @@
       'wm/cursor_manager_chromeos.cc',
       'wm/cursor_manager_chromeos.h',
       'wm/dim_window.cc',
       'wm/dim_window.h',
       'wm/drag_window_controller.cc',
       'wm/drag_window_controller.h',
       'wm/drag_window_resizer.cc',
       'wm/drag_window_resizer.h',
       'wm/event_client_impl.cc',
       'wm/event_client_impl.h',
+      'wm/forwarding_layer_delegate.cc',
+      'wm/forwarding_layer_delegate.h',
       'wm/gestures/overview_gesture_handler.cc',
       'wm/gestures/overview_gesture_handler.h',
       'wm/gestures/shelf_gesture_handler.cc',
       'wm/gestures/shelf_gesture_handler.h',
       'wm/immersive_fullscreen_controller.cc',
       'wm/immersive_fullscreen_controller.h',
       'wm/immersive_revealed_lock.cc',
       'wm/immersive_revealed_lock.h',
       'wm/lock_layout_manager.cc',
       'wm/lock_layout_manager.h',
@@ skipping 766 matching lines @@
                   '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
                 ],
               }
             ],
           ],
         },
       ],
     }],
   ],
 }