[Sync] Fixing easy lint violations.

components/sync/driver/startup_controller.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/driver/startup_controller.h"
 
-#include <string>
-
 #include "base/command_line.h"
 #include "base/location.h"
 #include "base/metrics/histogram_macros.h"
 #include "base/single_thread_task_runner.h"
 #include "base/strings/string_number_conversions.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "components/sync/driver/sync_driver_switches.h"
 #include "components/sync/driver/sync_prefs.h"
 
 namespace syncer {
@@ skipping 174 matching lines @@
   if (!start_up_time_.is_null()) {
     RecordTimeDeferred();
     UMA_HISTOGRAM_ENUMERATION("Sync.Startup.DeferredInitTrigger",
                               TRIGGER_DATA_TYPE_REQUEST, MAX_TRIGGER_VALUE);
   }
   received_start_request_ = true;
   TryStart();
 }
 
 }  // namespace syncer