[DeviceService] Add service tests for VibrationManager.

device/vibration/vibration_manager_impl.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 DEVICE_VIBRATION_VIBRATION_MANAGER_IMPL_H_
 #define DEVICE_VIBRATION_VIBRATION_MANAGER_IMPL_H_
 
 #include "device/vibration/vibration_export.h"
 #include "device/vibration/vibration_manager.mojom.h"
 
 namespace device {
 
 class VibrationManagerImpl {
  public:
   DEVICE_VIBRATION_EXPORT static void Create(
       mojo::InterfaceRequest<mojom::VibrationManager> request);
+
+  DEVICE_VIBRATION_EXPORT static int64_t milli_seconds_for_testing_;
+  DEVICE_VIBRATION_EXPORT static bool cancelled_for_testing_;
 };
 
 }  // namespace device
 
 #endif  // DEVICE_VIBRATION_VIBRATION_MANAGER_IMPL_H_