[Sync] Replace typedef with using.

components/sync/model/model_type_change_processor.h

 // Copyright 2015 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_MODEL_TYPE_CHANGE_PROCESSOR_H_
 #define COMPONENTS_SYNC_MODEL_MODEL_TYPE_CHANGE_PROCESSOR_H_
 
 #include <memory>
 #include <string>
 
 #include "base/callback.h"
 #include "base/location.h"
 #include "components/sync/base/model_type.h"
 #include "components/sync/engine/activation_context.h"
 #include "components/sync/model/entity_data.h"
 #include "components/sync/model/model_error.h"
 
 namespace syncer {
 
 class MetadataBatch;
 class MetadataChangeList;
 class ModelTypeSyncBridge;
 
 // Interface used by the ModelTypeSyncBridge to inform sync of local changes.
 class ModelTypeChangeProcessor {
  public:
-  typedef base::Callback<void(std::unique_ptr<ActivationContext>)>
-      StartCallback;
+  using StartCallback =
+      base::Callback<void(std::unique_ptr<ActivationContext>)>;
 
   // A factory function to make an implementation of ModelTypeChangeProcessor.
   static std::unique_ptr<ModelTypeChangeProcessor> Create(
       const base::RepeatingClosure& dump_stack,
       ModelType type,
       ModelTypeSyncBridge* bridge);
 
   ModelTypeChangeProcessor();
   virtual ~ModelTypeChangeProcessor();
 
@@ skipping 44 matching lines @@
   virtual void ReportError(const ModelError& error) = 0;
 
   // A convenience form of the above.
   virtual void ReportError(const tracked_objects::Location& location,
                            const std::string& message) = 0;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_MODEL_MODEL_TYPE_CHANGE_PROCESSOR_H_