[Sync] Clear access token on shutdown

components/browser_sync/browser/profile_sync_service.cc

 // Copyright (c) 2012 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.
 
 #include "components/browser_sync/browser/profile_sync_service.h"
 
 #include <cstddef>
 #include <map>
 #include <vector>
 
@@ skipping 880 matching lines @@
   backend_mode_ = IDLE;
   expect_sync_configuration_aborted_ = false;
   is_auth_in_progress_ = false;
   backend_initialized_ = false;
   cached_passphrase_.clear();
   encryption_pending_ = false;
   encrypt_everything_ = false;
   encrypted_types_ = syncer::SyncEncryptionHandler::SensitiveTypes();
   passphrase_required_reason_ = syncer::REASON_PASSPHRASE_NOT_REQUIRED;
   catch_up_configure_in_progress_ = false;
+  access_token_.clear();
   request_access_token_retry_timer_.Stop();
   // Revert to "no auth error".
   if (last_auth_error_.state() != GoogleServiceAuthError::NONE)
     UpdateAuthErrorState(GoogleServiceAuthError::AuthErrorNone());
 
   NotifyObservers();
 
   // Mark this as a clean shutdown(without crash).
   sync_prefs_.SetCleanShutdown(true);
 }
@@ skipping 1810 matching lines @@
 }
 
 std::string ProfileSyncService::unrecoverable_error_message() const {
   return unrecoverable_error_message_;
 }
 
 tracked_objects::Location ProfileSyncService::unrecoverable_error_location()
     const {
   return unrecoverable_error_location_;
 }