[Sync] Replace typedef with using.

components/sync/test/engine/mock_model_type_processor.h

 // Copyright 2014 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_TEST_ENGINE_MOCK_MODEL_TYPE_PROCESSOR_H_
 #define COMPONENTS_SYNC_TEST_ENGINE_MOCK_MODEL_TYPE_PROCESSOR_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 17 matching lines @@
 // ability to defer execution if we need to test race conditions, though.
 //
 // It maintains some state to try to make its behavior more realistic.  It
 // updates this state as it creates commit requests or receives update and
 // commit responses.
 //
 // It keeps a log of all received messages so tests can make assertions based
 // on their value.
 class MockModelTypeProcessor : public ModelTypeProcessor {
  public:
-  typedef base::Callback<void()> DisconnectCallback;
+  using DisconnectCallback = base::Callback<void()>;
 
   MockModelTypeProcessor();
   ~MockModelTypeProcessor() override;
 
   // Implementation of ModelTypeProcessor.
   void ConnectSync(std::unique_ptr<CommitQueue> commit_queue) override;
   void DisconnectSync() override;
   void OnCommitCompleted(const sync_pb::ModelTypeState& type_state,
                          const CommitResponseDataList& response_list) override;
   void OnUpdateReceived(const sync_pb::ModelTypeState& type_state,
@@ skipping 98 matching lines @@
 
   // Callback which will be call during disconnection
   DisconnectCallback disconnect_callback_;
 
   DISALLOW_COPY_AND_ASSIGN(MockModelTypeProcessor);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_TEST_ENGINE_MOCK_MODEL_TYPE_PROCESSOR_H_