Add non-blocking sync code to ProfileSyncService

sync/internal_api/public/test/fake_sync_manager.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.
 
 #ifndef SYNC_INTERNAL_API_PUBLIC_TEST_FAKE_SYNC_MANAGER_H_
 #define SYNC_INTERNAL_API_PUBLIC_TEST_FAKE_SYNC_MANAGER_H_
 
 #include <string>
 
 #include "base/memory/ref_counted.h"
@@ skipping 101 matching lines @@
       ModelTypeSet to_unapply,
       const ModelSafeRoutingInfo& new_routing_info,
       const base::Closure& ready_task,
       const base::Closure& retry_task) OVERRIDE;
   virtual void AddObserver(Observer* observer) OVERRIDE;
   virtual void RemoveObserver(Observer* observer) OVERRIDE;
   virtual SyncStatus GetDetailedStatus() const OVERRIDE;
   virtual void SaveChanges() OVERRIDE;
   virtual void ShutdownOnSyncThread() OVERRIDE;
   virtual UserShare* GetUserShare() OVERRIDE;
-  virtual syncer::SyncCore* GetSyncCore() OVERRIDE;
+  virtual base::WeakPtr<syncer::SyncCore> GetSyncCore() OVERRIDE;
   virtual const std::string cache_guid() OVERRIDE;
   virtual bool ReceivedExperiment(Experiments* experiments) OVERRIDE;
   virtual bool HasUnsyncedItems() OVERRIDE;
   virtual SyncEncryptionHandler* GetEncryptionHandler() OVERRIDE;
   virtual ScopedVector<syncer::ProtocolEvent>
       GetBufferedProtocolEvents() OVERRIDE;
   virtual void RefreshTypes(ModelTypeSet types) OVERRIDE;
 
  private:
   scoped_refptr<base::SequencedTaskRunner> sync_task_runner_;
@@ skipping 27 matching lines @@
   scoped_ptr<FakeSyncEncryptionHandler> fake_encryption_handler_;
 
   TestUserShare test_user_share_;
 
   DISALLOW_COPY_AND_ASSIGN(FakeSyncManager);
 };
 
 }  // namespace syncer
 
 #endif  // SYNC_INTERNAL_API_PUBLIC_TEST_FAKE_SYNC_MANAGER_H_