Revert 150990 - [Sync] Avoid unregistering object IDs on shutdown

sync/notifier/sync_notifier_factory_unittest.cc

Index: sync/notifier/sync_notifier_factory_unittest.cc
===================================================================
--- sync/notifier/sync_notifier_factory_unittest.cc	(revision 150991)
+++ sync/notifier/sync_notifier_factory_unittest.cc	(working copy)
@@ -61,9 +61,8 @@
 #else
   ASSERT_TRUE(notifier.get());
   ObjectIdSet ids = ModelTypeSetToObjectIdSet(ModelTypeSet(syncer::BOOKMARKS));
-  notifier->RegisterHandler(&mock_observer_);
   notifier->UpdateRegisteredIds(&mock_observer_, ids);
-  notifier->UnregisterHandler(&mock_observer_);
+  notifier->UpdateRegisteredIds(&mock_observer_, ObjectIdSet());
 #endif
 }
 
@@ -80,9 +79,8 @@
 #else
   ASSERT_TRUE(notifier.get());
   ObjectIdSet ids = ModelTypeSetToObjectIdSet(ModelTypeSet(syncer::BOOKMARKS));
-  notifier->RegisterHandler(&mock_observer_);
   notifier->UpdateRegisteredIds(&mock_observer_, ids);
-  notifier->UnregisterHandler(&mock_observer_);
+  notifier->UpdateRegisteredIds(&mock_observer_, ObjectIdSet());
 #endif
 }