[Sync] Fixing sync_driver lint violations and adding PRESUBMIT lint check.

components/sync_driver/sync_frontend.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_SYNC_FRONTEND_H_
 #define COMPONENTS_SYNC_DRIVER_SYNC_FRONTEND_H_
 
+#include <string>
+
 #include "base/basictypes.h"
 #include "sync/internal_api/public/base/model_type.h"
 #include "sync/internal_api/public/sync_encryption_handler.h"
 #include "sync/internal_api/public/sync_manager.h"
 #include "sync/internal_api/public/util/weak_handle.h"
 #include "sync/protocol/sync_protocol_error.h"
 
 namespace syncer {
 class DataTypeDebugInfoListener;
 class JsBackend;
@@ skipping 122 matching lines @@
   // |nigori_state| contains the new (post custom passphrase) encryption keys
   // and can be used to restore SyncEncryptionHandler's state across sync
   // backend instances. See also SyncEncryptionHandlerImpl::RestoreNigori.
   virtual void OnLocalSetPassphraseEncryption(
       const syncer::SyncEncryptionHandler::NigoriState& nigori_state) = 0;
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_SYNC_FRONTEND_H_