Remove Chromecast extension support from cast system tray menu.

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 1254 matching lines @@
       "ash/app_list/app_sync_ui_state_watcher.h",
       "ash/app_sync_ui_state.cc",
       "ash/app_sync_ui_state.h",
       "ash/app_sync_ui_state_factory.cc",
       "ash/app_sync_ui_state_factory.h",
       "ash/app_sync_ui_state_observer.h",
       "ash/ash_init.cc",
       "ash/ash_init.h",
       "ash/ash_util.cc",
       "ash/ash_util.h",
-      "ash/cast_config_delegate_chromeos.cc",
-      "ash/cast_config_delegate_chromeos.h",
       "ash/cast_config_delegate_media_router.cc",
       "ash/cast_config_delegate_media_router.h",
       "ash/chrome_keyboard_ui.cc",
       "ash/chrome_keyboard_ui.h",
       "ash/chrome_launcher_prefs.cc",
       "ash/chrome_launcher_prefs.h",
       "ash/chrome_new_window_client.cc",
       "ash/chrome_new_window_client.h",
       "ash/chrome_screenshot_grabber.cc",
       "ash/chrome_screenshot_grabber.h",
@@ skipping 2143 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" ]
   }
 }