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

components/sync_driver/device_info_tracker.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_DEVICE_INFO_TRACKER_H_
 #define COMPONENTS_SYNC_DRIVER_DEVICE_INFO_TRACKER_H_
 
+#include <string>
+
 #include "base/memory/scoped_ptr.h"
 #include "base/memory/scoped_vector.h"
 #include "components/sync_driver/device_info.h"
 
 namespace sync_driver {
 
 // Interface for tracking synced DeviceInfo.
 class DeviceInfoTracker {
  public:
   virtual ~DeviceInfoTracker() {}
@@ skipping 15 matching lines @@
   virtual ScopedVector<DeviceInfo> GetAllDeviceInfo() const = 0;
   // Registers an observer to be called on syncing any updated DeviceInfo.
   virtual void AddObserver(Observer* observer) = 0;
   // Unregisters an observer.
   virtual void RemoveObserver(Observer* observer) = 0;
 };
 
 }  // namespace sync_driver
 
 #endif  // COMPONENTS_SYNC_DRIVER_DEVICE_INFO_TRACKER_H_