Add KeyedServiceShutdownNotifier for classes that depend on keyed services but can't be keyed servi…

components/keyed_service/core/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.
 
 component("core") {
   output_name = "keyed_service_core"
   sources = [
     "dependency_graph.cc",
     "dependency_graph.h",
     "dependency_manager.cc",
     "dependency_manager.h",
     "dependency_node.h",
     "keyed_service.cc",
     "keyed_service.h",
     "keyed_service_base_factory.cc",
     "keyed_service_base_factory.h",
     "keyed_service_export.h",
     "keyed_service_factory.cc",
     "keyed_service_factory.h",
+    "keyed_service_shutdown_notifier.cc",
+    "keyed_service_shutdown_notifier.h",
     "refcounted_keyed_service.cc",
     "refcounted_keyed_service.h",
     "refcounted_keyed_service_factory.cc",
     "refcounted_keyed_service_factory.h",
     "service_access_types.h",
   ]
 
   defines = [ "KEYED_SERVICE_IMPLEMENTATION" ]
 
   deps = [
     "//base",
   ]
 
   if (is_win) {
     # TODO(jschuh): crbug.com/167187 fix size_t to int truncations.
     cflags = [ "/wd4267" ]
   }
 }