[Sync] Replace typedef with using.

components/sync/test/fake_server/fake_server.cc

 // 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.
 
 #include "components/sync/test/fake_server/fake_server.h"
 
 #include <algorithm>
 #include <limits>
 #include <set>
 #include <utility>
@@ skipping 70 matching lines @@
   bool ClientWantsItem(const FakeServerEntity& entity) {
     int64_t version = entity.GetVersion();
     ModelType type = entity.model_type();
     response_version_map_[type] =
         std::max(response_version_map_[type], version);
     auto it = request_version_map_.find(type);
     return it == request_version_map_.end() ? false : it->second < version;
   }
 
  private:
-  typedef std::map<ModelType, int64_t> ModelTypeToVersionMap;
+  using ModelTypeToVersionMap = std::map<ModelType, int64_t>;
 
   static UpdateSieve::ModelTypeToVersionMap MessageToVersionMap(
       const sync_pb::GetUpdatesMessage& get_updates_message) {
     CHECK_GT(get_updates_message.from_progress_marker_size(), 0)
         << "A GetUpdates request must have at least one progress marker.";
     ModelTypeToVersionMap request_version_map;
 
     for (int i = 0; i < get_updates_message.from_progress_marker_size(); i++) {
       sync_pb::DataTypeProgressMarker marker =
           get_updates_message.from_progress_marker(i);
@@ skipping 598 matching lines @@
   DCHECK(thread_checker_.CalledOnValidThread());
   return weak_ptr_factory_.GetWeakPtr();
 }
 
 std::string FakeServer::GetStoreBirthday() const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return base::Int64ToString(store_birthday_);
 }
 
 }  // namespace fake_server