chromeos: Refactor system tray "show settings" commands to use mojo

chrome/browser/ui/BUILD.gn

 # 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.
 
 import("//build/config/chromecast_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 1185 matching lines @@
       "app_list/search/launcher_search/launcher_search_icon_image_loader.cc",
       "app_list/search/launcher_search/launcher_search_icon_image_loader.h",
       "app_list/search/launcher_search/launcher_search_icon_image_loader_impl.cc",
       "app_list/search/launcher_search/launcher_search_icon_image_loader_impl.h",
       "app_list/search/launcher_search/launcher_search_provider.cc",
       "app_list/search/launcher_search/launcher_search_provider.h",
       "app_list/search/launcher_search/launcher_search_result.cc",
       "app_list/search/launcher_search/launcher_search_result.h",
       "ash/system_tray_client.cc",
       "ash/system_tray_client.h",
-      "ash/system_tray_common.cc",
-      "ash/system_tray_common.h",
       "extensions/extension_installed_notification.cc",
       "extensions/extension_installed_notification.h",
       "input_method/input_method_engine_base.cc",
       "input_method/input_method_engine_base.h",
       "views/apps/chrome_native_app_window_views_aura_ash.cc",
       "views/apps/chrome_native_app_window_views_aura_ash.h",
       "views/intent_picker_bubble_view.cc",
       "views/intent_picker_bubble_view.h",
 
       # On chromeos, file manager extension handles the file open/save dialog.
@@ skipping 2205 matching lines @@
       "test/test_confirm_bubble_model.cc",
       "test/test_confirm_bubble_model.h",
     ]
     deps += [ "//chrome/test:test_support_ui" ]
   }
 
   if (enable_extensions) {
     deps += [ "//extensions/browser" ]
   }
 }