[Sync] Replace typedef with using.

components/sync/model/syncable_service.h

 // Copyright 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 COMPONENTS_SYNC_MODEL_SYNCABLE_SERVICE_H_
 #define COMPONENTS_SYNC_MODEL_SYNCABLE_SERVICE_H_
 
 #include <memory>
 #include <vector>
 
@@ skipping 18 matching lines @@
 class SyncableService : public SyncChangeProcessor,
                         public base::SupportsWeakPtr<SyncableService> {
  public:
   // A StartSyncFlare is useful when your SyncableService has a need for sync
   // to start ASAP, typically because a local change event has occurred but
   // MergeDataAndStartSyncing hasn't been called yet, meaning you don't have a
   // SyncChangeProcessor. The sync subsystem will respond soon after invoking
   // Run() on your flare by calling MergeDataAndStartSyncing. The ModelType
   // parameter is included so that the recieving end can track usage and timing
   // statistics, make optimizations or tradeoffs by type, etc.
-  typedef base::Callback<void(ModelType)> StartSyncFlare;
+  using StartSyncFlare = base::Callback<void(ModelType)>;
 
   // Informs the service to begin syncing the specified synced datatype |type|.
   // The service should then merge |initial_sync_data| into it's local data,
   // calling |sync_processor|'s ProcessSyncChanges as necessary to reconcile the
   // two. After this, the SyncableService's local data should match the server
   // data, and the service should be ready to receive and process any further
   // SyncChange's as they occur.
   // Returns: a SyncMergeResult whose error field reflects whether an error
   //          was encountered while merging the two models. The merge result
   //          may also contain optional merge statistics.
@@ skipping 36 matching lines @@
   virtual void SetAttachmentService(
       std::unique_ptr<AttachmentService> attachment_service);
 
  protected:
   ~SyncableService() override;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_MODEL_SYNCABLE_SERVICE_H_