[Sync] Avoid unregistering object IDs on shutdown

sync/notifier/non_blocking_invalidation_notifier.h

 // 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.
 //
 // An implementation of SyncNotifier that wraps InvalidationNotifier
 // on its own thread.
 
 #ifndef SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_
 #define SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_
 
 #include <string>
 
 #include "base/basictypes.h"
 #include "base/compiler_specific.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "jingle/notifier/base/notifier_options.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 #include "sync/notifier/invalidation_state_tracker.h"
 #include "sync/notifier/sync_notifier.h"
-#include "sync/notifier/sync_notifier_helper.h"
 #include "sync/notifier/sync_notifier_observer.h"
+#include "sync/notifier/sync_notifier_registrar.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }  // namespace base
 
 namespace syncer {
 
+// TODO(akalin): Generalize to NonBlockingSyncNotifier
+// (http://crbug.com/140409).
 class NonBlockingInvalidationNotifier
     : public SyncNotifier,
       // SyncNotifierObserver to "observe" our Core via WeakHandle.
       public SyncNotifierObserver {
  public:
   // |invalidation_state_tracker| must be initialized.
   NonBlockingInvalidationNotifier(
       const notifier::NotifierOptions& notifier_options,
       const InvalidationVersionMap& initial_max_invalidation_versions,
       const std::string& initial_invalidation_state,
       const WeakHandle<InvalidationStateTracker>&
           invalidation_state_tracker,
       const std::string& client_info);
 
   virtual ~NonBlockingInvalidationNotifier();
 
   // SyncNotifier implementation.
+  virtual void RegisterHandler(SyncNotifierObserver* handler) OVERRIDE;
   virtual void UpdateRegisteredIds(SyncNotifierObserver* handler,
                                    const ObjectIdSet& ids) OVERRIDE;
+  virtual void UnregisterHandler(SyncNotifierObserver* handler) OVERRIDE;
   virtual void SetUniqueId(const std::string& unique_id) OVERRIDE;
   virtual void SetStateDeprecated(const std::string& state) OVERRIDE;
   virtual void UpdateCredentials(
       const std::string& email, const std::string& token) OVERRIDE;
   virtual void SendNotification(ModelTypeSet changed_types) OVERRIDE;
 
   // SyncNotifierObserver implementation.
   virtual void OnNotificationsEnabled() OVERRIDE;
   virtual void OnNotificationsDisabled(
       NotificationsDisabledReason reason) OVERRIDE;
   virtual void OnIncomingNotification(
       const ObjectIdPayloadMap& id_payloads,
       IncomingNotificationSource source) OVERRIDE;
 
  private:
   class Core;
 
   base::WeakPtrFactory<NonBlockingInvalidationNotifier> weak_ptr_factory_;
 
-  SyncNotifierHelper helper_;
+  SyncNotifierRegistrar registrar_;
 
   // The real guts of NonBlockingInvalidationNotifier, which allows
   // this class to live completely on the parent thread.
   scoped_refptr<Core> core_;
   scoped_refptr<base::SingleThreadTaskRunner> parent_task_runner_;
   scoped_refptr<base::SingleThreadTaskRunner> network_task_runner_;
 
   DISALLOW_COPY_AND_ASSIGN(NonBlockingInvalidationNotifier);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_NOTIFIER_NON_BLOCKING_INVALIDATION_NOTIFIER_H_