[DeviceService] Expose battery monitoring solely via the Device Service

device/battery/battery_status_manager.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_BATTERY_BATTERY_STATUS_MANAGER_H_
-#define DEVICE_BATTERY_BATTERY_STATUS_MANAGER_H_
-
-#include <memory>
-
-#include "device/battery/battery_status_service.h"
-
-namespace device {
-
-// Platform specific manager class for fetching battery status data.
-class BatteryStatusManager {
- public:
-  // Creates a BatteryStatusManager object. |callback| should be called when the
-  // battery status changes.
-  static std::unique_ptr<BatteryStatusManager> Create(
-      const BatteryStatusService::BatteryUpdateCallback& callback);
-
-  virtual ~BatteryStatusManager() {}
-
-  // Start listening for battery status changes. New updates are signalled
-  // by invoking the callback provided at construction time.
-  // Note that this is called in the IO thread.
-  virtual bool StartListeningBatteryChange() = 0;
-
-  // Stop listening for battery status changes.
-  // Note that this is called in the IO thread.
-  virtual void StopListeningBatteryChange() = 0;
-};
-
-}  // namespace device
-
-#endif  // DEVICE_BATTERY_BATTERY_STATUS_MANAGER_H_