[Sync] Avoid unregistering object IDs on shutdown

chrome/browser/sync/profile_sync_service.cc

Index: chrome/browser/sync/profile_sync_service.cc
diff --git a/chrome/browser/sync/profile_sync_service.cc b/chrome/browser/sync/profile_sync_service.cc
index ca3926fc6acb27490d83a7f577754ec6b2792c48..d18185fb20d35e134e01b0bd1555fcb57fa510b7 100644
--- a/chrome/browser/sync/profile_sync_service.cc
+++ b/chrome/browser/sync/profile_sync_service.cc
@@ -428,7 +428,8 @@ void ProfileSyncService::StartUp() {
   // TODO(akalin): Fix this horribly non-intuitive behavior (see
   // http://crbug.com/140354).
   if (backend_.get()) {
-    backend_->UpdateRegisteredInvalidationIds(all_registered_ids_);
+    backend_->UpdateRegisteredInvalidationIds(
+        notifier_registrar_.GetAllRegisteredIds());
   }
 
   if (!sync_global_error_.get()) {
@@ -441,17 +442,29 @@ void ProfileSyncService::StartUp() {
   }
 }
 
+void ProfileSyncService::RegisterInvalidationHandler(
+    syncer::SyncNotifierObserver* handler) {
+  notifier_registrar_.RegisterHandler(handler);
+}
+
 void ProfileSyncService::UpdateRegisteredInvalidationIds(
     syncer::SyncNotifierObserver* handler,
     const syncer::ObjectIdSet& ids) {
-  all_registered_ids_ = notifier_helper_.UpdateRegisteredIds(handler, ids);
+  notifier_registrar_.UpdateRegisteredIds(handler, ids);
+
   // If |backend_| is NULL, its registered IDs will be updated when
   // it's created and initialized.
   if (backend_.get()) {
-    backend_->UpdateRegisteredInvalidationIds(all_registered_ids_);
+    backend_->UpdateRegisteredInvalidationIds(
+        notifier_registrar_.GetAllRegisteredIds());
   }
 }
 
+void ProfileSyncService::UnregisterInvalidationHandler(
+    syncer::SyncNotifierObserver* handler) {
+  notifier_registrar_.UnregisterHandler(handler);
+}
+
 void ProfileSyncService::Shutdown() {
   ShutdownImpl(false);
 }
@@ -464,7 +477,6 @@ void ProfileSyncService::ShutdownImpl(bool sync_disabled) {
   base::Time shutdown_start_time = base::Time::Now();
   if (backend_.get()) {
     backend_->StopSyncingForShutdown();
-    backend_->UpdateRegisteredInvalidationIds(syncer::ObjectIdSet());
   }
 
   // Stop all data type controllers, if needed.  Note that until Stop
@@ -659,18 +671,18 @@ void ProfileSyncService::DisableBrokenDatatype(
 }
 
 void ProfileSyncService::OnNotificationsEnabled() {
-  notifier_helper_.EmitOnNotificationsEnabled();
+  notifier_registrar_.EmitOnNotificationsEnabled();
 }
 
 void ProfileSyncService::OnNotificationsDisabled(
     syncer::NotificationsDisabledReason reason) {
-  notifier_helper_.EmitOnNotificationsDisabled(reason);
+  notifier_registrar_.EmitOnNotificationsDisabled(reason);
 }
 
 void ProfileSyncService::OnIncomingNotification(
     const syncer::ObjectIdPayloadMap& id_payloads,
     syncer::IncomingNotificationSource source) {
-  notifier_helper_.DispatchInvalidationsToHandlers(id_payloads, source);
+  notifier_registrar_.DispatchInvalidationsToHandlers(id_payloads, source);
 }
 
 void ProfileSyncService::OnBackendInitialized(