[Sync] Replace typedef with using.

components/sync/engine_impl/debug_info_event_listener.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_ENGINE_IMPL_DEBUG_INFO_EVENT_LISTENER_H_
 #define COMPONENTS_SYNC_ENGINE_IMPL_DEBUG_INFO_EVENT_LISTENER_H_
 
 #include <deque>
 #include <string>
 #include <vector>
@@ skipping 76 matching lines @@
 
  private:
   FRIEND_TEST_ALL_PREFIXES(DebugInfoEventListenerTest, VerifyEventsAdded);
   FRIEND_TEST_ALL_PREFIXES(DebugInfoEventListenerTest, VerifyQueueSize);
   FRIEND_TEST_ALL_PREFIXES(DebugInfoEventListenerTest, VerifyGetEvents);
   FRIEND_TEST_ALL_PREFIXES(DebugInfoEventListenerTest, VerifyClearEvents);
 
   void AddEventToQueue(const sync_pb::DebugEventInfo& event_info);
   void CreateAndAddEvent(sync_pb::SyncEnums::SingletonDebugEventType type);
 
-  typedef std::deque<sync_pb::DebugEventInfo> DebugEventInfoQueue;
+  using DebugEventInfoQueue = std::deque<sync_pb::DebugEventInfo>;
   DebugEventInfoQueue events_;
 
   // True indicates we had to drop one or more events to keep our limit of
   // |kMaxEntries|.
   bool events_dropped_;
 
   // Cryptographer has keys that are not yet decrypted.
   bool cryptographer_has_pending_keys_;
 
   // Cryptographer is initialized and does not have pending keys.
   bool cryptographer_ready_;
 
   base::ThreadChecker thread_checker_;
 
   base::WeakPtrFactory<DebugInfoEventListener> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(DebugInfoEventListener);
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_ENGINE_IMPL_DEBUG_INFO_EVENT_LISTENER_H_