Add generic PaletteDelegate code.

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_aura.cc',
@@ skipping 67 matching lines @@
       'common/gpu_support_stub.h',
       'common/keyboard/keyboard_ui.cc',
       'common/keyboard/keyboard_ui.h',
       'common/keyboard/keyboard_ui_observer.h',
       'common/login_status.h',
       'common/material_design/material_design_controller.cc',
       'common/material_design/material_design_controller.h',
       'common/metrics/user_metrics_action.h',
       'common/multi_profile_uma.cc',
       'common/multi_profile_uma.h',
+      'common/palette_delegate.h',
       'common/pointer_watcher_delegate.h',
       'common/popup_message.cc',
       'common/popup_message.h',
       'common/root_window_controller_common.cc',
       'common/root_window_controller_common.h',
       'common/scoped_root_window_for_new_windows.cc',
       'common/scoped_root_window_for_new_windows.h',
       'common/session/session_state_delegate.cc',
       'common/session/session_state_delegate.h',
       'common/session/session_state_observer.cc',
@@ skipping 1380 matching lines @@
                   '../tools/xdisplaycheck/xdisplaycheck.gyp:xdisplaycheck',
                 ],
               }
             ],
           ],
         },
       ],
     }],
   ],
 }