[Sync] Fixing easy lint violations.

components/sync/driver/startup_controller.h

 // 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.
 
 #ifndef COMPONENTS_SYNC_DRIVER_STARTUP_CONTROLLER_H_
 #define COMPONENTS_SYNC_DRIVER_STARTUP_CONTROLLER_H_
 
+#include <string>
+
 #include "base/callback.h"
 #include "base/memory/weak_ptr.h"
 #include "base/time/time.h"
 #include "components/sync/base/model_type.h"
 
 namespace syncer {
 
 class SyncPrefs;
 
 // This class is used by ProfileSyncService to manage all logic and state
@@ skipping 85 matching lines @@
 
   // Used to compute preferred_types from SyncPrefs as-needed.
   ModelTypeSet registered_types_;
 
   base::WeakPtrFactory<StartupController> weak_factory_;
 };
 
 }  // namespace syncer
 
 #endif  // COMPONENTS_SYNC_DRIVER_STARTUP_CONTROLLER_H_