Remove Chromecast extension support from cast system tray menu.

chrome/browser/extensions/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/features.gni")
 import("//build/config/ui.gni")
 import("//chrome/common/features.gni")
 
 assert(enable_extensions)
 
@@ skipping 900 matching lines @@
     "//ui/strings",
     "//url",
   ]
 
   if (!is_chromeos) {
     sources += [ "chrome_kiosk_delegate.cc" ]
   }
 
   if (is_chromeos) {
     sources += [
-      "api/cast_devices_private/cast_devices_private_api.cc",
-      "api/cast_devices_private/cast_devices_private_api.h",
       "api/certificate_provider/certificate_provider_api.cc",
       "api/certificate_provider/certificate_provider_api.h",
       "api/enterprise_device_attributes/enterprise_device_attributes_api.cc",
       "api/enterprise_device_attributes/enterprise_device_attributes_api.h",
       "api/enterprise_platform_keys/enterprise_platform_keys_api.cc",
       "api/enterprise_platform_keys/enterprise_platform_keys_api.h",
       "api/enterprise_platform_keys_private/enterprise_platform_keys_private_api.cc",
       "api/enterprise_platform_keys_private/enterprise_platform_keys_private_api.h",
       "api/file_system/request_file_system_dialog_view.cc",
       "api/file_system/request_file_system_dialog_view.h",
@@ skipping 244 matching lines @@
       "api/braille_display_private/brlapi_connection.cc",
       "api/braille_display_private/brlapi_connection.h",
       "api/braille_display_private/brlapi_keycode_map.cc",
       "api/braille_display_private/brlapi_keycode_map.h",
     ]
     deps += [ "//build/linux/libbrlapi" ]
   } else {
     sources += [ "api/braille_display_private/braille_controller_stub.cc" ]
   }
 }