[Sync] Replace typedef with using.

components/sync_sessions/lost_navigations_recorder_unittest.cc

 // Copyright 2016 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_sessions/lost_navigations_recorder.h"
 
 #include <memory>
 #include <string>
 
 #include "base/message_loop/message_loop.h"
 #include "base/test/histogram_tester.h"
 #include "components/sync/model/attachments/attachment_service_proxy_for_test.h"
 #include "components/sync/syncable/entry.h"
 #include "components/sync/syncable/mutable_entry.h"
 #include "components/sync/syncable/syncable_base_transaction.h"
 #include "components/sync/syncable/syncable_read_transaction.h"
 #include "components/sync/syncable/syncable_write_transaction.h"
 #include "components/sync/test/engine/test_directory_setter_upper.h"
 #include "components/sync/test/engine/test_id_factory.h"
 #include "components/sync_sessions/sessions_sync_manager.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 using syncer::syncable::Entry;
 using syncer::syncable::Id;
 using syncer::syncable::MutableEntry;
 using syncer::syncable::WriteTransaction;
 
 namespace sync_sessions {
 namespace {
-typedef SessionID::id_type id_type;
+using id_type = SessionID::id_type;
 
 const char kTab1SyncTag[] = "tab-YWRkcjHvv74=";
 const char kTab2SyncTag[] = "tab-2FyZDHvv74=";
 
 class LostNavigationsRecorderTest : public testing::Test {
  protected:
   void SetUp() override {
     dir_maker_.SetUp();
     _id = 1;
   }
@@ skipping 349 matching lines @@
       ->DeleteSubrange(0, 2);
   RecordChange(&mutable_entry, specifics);
 
   TriggerReconcile(&mutable_entry, true, &specifics);
 
   histogram_tester.ExpectBucketCount("Sync.LostNavigationCount", 2, 1);
 }
 
 };  // namespace
 };  // namespace sync_sessions