Add ArcEnabled policy implementation

chrome/browser/chromeos/arc/arc_auth_service.h

 // Copyright 2016 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.
 
 #ifndef CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_SERVICE_H_
 #define CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_SERVICE_H_
 
 #include <ostream>
 
 #include "base/macros.h"
 #include "base/observer_list.h"
 #include "base/threading/thread_checker.h"
 #include "components/arc/arc_bridge_service.h"
 #include "components/arc/arc_service.h"
 #include "components/arc/auth/arc_auth_fetcher.h"
 #include "components/arc/common/auth.mojom.h"
+#include "components/prefs/pref_change_registrar.h"
 #include "components/syncable_prefs/pref_service_syncable_observer.h"
 #include "components/syncable_prefs/synced_pref_observer.h"
 #include "google_apis/gaia/gaia_auth_consumer.h"
 #include "google_apis/gaia/ubertoken_fetcher.h"
 #include "mojo/public/cpp/bindings/binding.h"
 
 class GaiaAuthFetcher;
 class Profile;
 
 namespace content {
@@ skipping 136 matching lines @@
   void ShutdownBridgeAndShowUI(UIPage page, const base::string16& status);
   void OnOptInPreferenceChanged();
   void FetchAuthCode();
 
   // Unowned pointer. Keeps current profile.
   Profile* profile_ = nullptr;
   // Owned by content::BrowserContent. Used to isolate cookies for auth server
   // communication and shared with Arc OptIn UI platform app.
   content::StoragePartition* storage_partition_ = nullptr;
 
+  // Registrar used to monitor ARC enabled state.
+  PrefChangeRegistrar pref_change_registrar_;
+
   mojo::Binding<AuthHost> binding_;
   base::ThreadChecker thread_checker_;
   State state_ = State::STOPPED;
   base::ObserverList<Observer> observer_list_;
   scoped_ptr<ArcAuthFetcher> auth_fetcher_;
   scoped_ptr<GaiaAuthFetcher> merger_fetcher_;
   scoped_ptr<UbertokenFetcher> ubertoken_fethcher_;
   std::string auth_code_;
   GetAuthCodeCallback auth_callback_;
   bool initial_opt_in_ = false;
   bool context_prepared_ = false;
   UIPage ui_page_ = UIPage::NO_PAGE;
   base::string16 ui_page_status_;
 
   DISALLOW_COPY_AND_ASSIGN(ArcAuthService);
 };
 
 std::ostream& operator<<(std::ostream& os, const ArcAuthService::State& state);
 
 }  // namespace arc
 
 #endif  // CHROME_BROWSER_CHROMEOS_ARC_ARC_AUTH_SERVICE_H_