[Sync] Notify invalidation handlers when sync is disabled/enabled

chrome/browser/sync/profile_sync_service.h

Index: chrome/browser/sync/profile_sync_service.h
diff --git a/chrome/browser/sync/profile_sync_service.h b/chrome/browser/sync/profile_sync_service.h
index bfeb6761c9e3d096e6ab9e124a388efd8b696db9..7bac085f84a16e970600c5248b888175444a32e7 100644
--- a/chrome/browser/sync/profile_sync_service.h
+++ b/chrome/browser/sync/profile_sync_service.h
@@ -715,6 +715,11 @@ class ProfileSyncService : public ProfileSyncServiceBase,
                                     bool delete_sync_database,
                                     UnrecoverableErrorReason reason);
 
+  // Must be called every time |backend_initialized_| or
+  // |invalidator_state_| is changed (but only if
+  // |invalidator_registrar_| is not NULL).
+  void UpdateInvalidatorRegistrarState();
+
   // Destroys / recreates an instance of ProfileSyncService. Used exclusively by
   // the sync integration tests so they can restart sync from scratch without
   // tearing down and recreating the browser process. Needed because simply
@@ -843,6 +848,12 @@ class ProfileSyncService : public ProfileSyncServiceBase,
   // Factory the backend will use to build the SyncManager.
   syncer::SyncManagerFactory sync_manager_factory_;
 
+  // Holds the current invalidator state as updated by
+  // OnInvalidatorStateChange().  Note that this is different from the
+  // state known by |invalidator_registrar_| (See
+  // UpdateInvalidatorState()).
+  syncer::InvalidatorState invalidator_state_;
+
   // Dispatches invalidations to handlers.  Set in Initialize() and
   // unset in Shutdown().
   scoped_ptr<syncer::InvalidatorRegistrar> invalidator_registrar_;