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

components/sync_driver/generic_change_processor_unittest.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/generic_change_processor.h"
 
+#include <string>
+
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/weak_ptr.h"
 #include "base/message_loop/message_loop.h"
 #include "base/run_loop.h"
 #include "base/strings/stringprintf.h"
 #include "components/sync_driver/data_type_error_handler_mock.h"
 #include "components/sync_driver/fake_sync_client.h"
 #include "components/sync_driver/local_device_info_provider.h"
 #include "components/sync_driver/sync_api_component_factory.h"
 #include "sync/api/attachments/attachment_id.h"
@@ skipping 520 matching lines @@
   syncer::SyncDataList sync_data =
       change_processor()->GetAllSyncData(syncer::SESSIONS);
   ASSERT_EQ(sync_data.size(), 1U);
   ASSERT_EQ("session tag 2",
             sync_data[0].GetSpecifics().session().session_tag());
 }
 
 }  // namespace
 
 }  // namespace sync_driver