Remove Chromecast extension support from cast system tray menu.

chrome/common/extensions/api/BUILD.gn

 # Copyright 2015 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("//build/json_schema_api.gni")
 import("//chrome/common/features.gni")
 import("//tools/json_schema_compiler/json_features.gni")
 
@@ skipping 73 matching lines @@
   "webrtc_logging_private.idl",
   "webstore_private.json",
   "webstore_widget_private.idl",
   "windows.json",
 ]
 if (enable_task_manager) {
   schema_sources += [ "processes.idl" ]
 }
 if (is_chromeos) {
   schema_sources += [
-    "cast_devices_private.idl",
     "certificate_provider.idl",
     "certificate_provider_internal.idl",
     "echo_private.json",
     "enterprise_device_attributes.idl",
     "enterprise_platform_keys.idl",
     "enterprise_platform_keys_internal.idl",
     "enterprise_platform_keys_private.json",
     "file_browser_handler_internal.json",
     "file_manager_private.idl",
     "file_manager_private_internal.idl",
@@ skipping 162 matching lines @@
 }
 
 group("extensions_features") {
   public_deps = [
     ":api_features",
     ":behavior_features",
     ":manifest_features",
     ":permission_features",
   ]
 }