[Sync] Replace typedef with using.

components/sync/engine_impl/sync_scheduler_impl_unittest.cc

 // Copyright (c) 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.
 
 #include "components/sync/engine_impl/sync_scheduler_impl.h"
 
 #include <stddef.h>
 #include <stdint.h>
 
 #include <vector>
@@ skipping 41 matching lines @@
   MOCK_METHOD3(NormalSyncShare, bool(ModelTypeSet, NudgeTracker*, SyncCycle*));
   MOCK_METHOD3(ConfigureSyncShare,
                bool(ModelTypeSet,
                     sync_pb::GetUpdatesCallerInfo::GetUpdatesSource,
                     SyncCycle*));
   MOCK_METHOD2(PollSyncShare, bool(ModelTypeSet, SyncCycle*));
 };
 
 MockSyncer::MockSyncer() : Syncer(nullptr) {}
 
-typedef std::vector<TimeTicks> SyncShareTimes;
+using SyncShareTimes = std::vector<TimeTicks>;
 
 void QuitLoopNow() {
   // We use QuitNow() instead of Quit() as the latter may get stalled
   // indefinitely in the presence of repeated timers with low delays
   // and a slow test (e.g., ThrottlingDoesThrottle [which has a poll
   // delay of 5ms] run under TSAN on the trybots).
   base::MessageLoop::current()->QuitNow();
 }
 
 void RunLoop() {
@@ skipping 1681 matching lines @@
 
   // The Exponential backoff should be between previous backoff 1.5 and 2.5
   // times.
   EXPECT_LE(first_blocking_time * 1.5, second_blocking_time);
   EXPECT_GE(first_blocking_time * 2.5, second_blocking_time);
 
   StopSyncScheduler();
 }
 
 }  // namespace syncer