[Sync] Replace typedef with using.

components/sync/driver/glue/sync_backend_host_impl.h

 // Copyright 2013 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 COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 #define COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_IMPL_H_
 
 #include <stdint.h>
 
 #include <map>
@@ skipping 29 matching lines @@
 class ChangeProcessor;
 class SyncBackendHostCore;
 class SyncBackendRegistrar;
 class SyncClient;
 class SyncPrefs;
 
 // The only real implementation of the SyncEngine. See that interface's
 // definition for documentation of public methods.
 class SyncBackendHostImpl : public SyncEngine, public InvalidationHandler {
  public:
-  typedef SyncStatus Status;
+  using Status = SyncStatus;
 
   SyncBackendHostImpl(const std::string& name,
                       SyncClient* sync_client,
                       invalidation::InvalidationService* invalidator,
                       const base::WeakPtr<SyncPrefs>& sync_prefs,
                       const base::FilePath& sync_data_folder);
   ~SyncBackendHostImpl() override;
 
   // SyncEngine implementation.
   void Initialize(InitParams params) override;
@@ skipping 167 matching lines @@
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<SyncBackendHostImpl> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(SyncBackendHostImpl);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_GLUE_SYNC_BACKEND_HOST_IMPL_H_