[DeviceService] Expose battery monitoring solely via the Device Service

device/battery/battery_status_service.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_SERVICE_H_
-#define DEVICE_BATTERY_BATTERY_STATUS_SERVICE_H_
-
-#include <memory>
-
-#include "base/callback_list.h"
-#include "base/macros.h"
-#include "base/memory/singleton.h"
-#include "device/battery/battery_export.h"
-#include "device/battery/battery_status.mojom.h"
-
-namespace base {
-class SingleThreadTaskRunner;
-}
-
-namespace device {
-class BatteryStatusManager;
-
-class DEVICE_BATTERY_EXPORT BatteryStatusService {
- public:
-  typedef base::Callback<void(const mojom::BatteryStatus&)>
-      BatteryUpdateCallback;
-  typedef base::CallbackList<void(const mojom::BatteryStatus&)>
-      BatteryUpdateCallbackList;
-  typedef BatteryUpdateCallbackList::Subscription BatteryUpdateSubscription;
-
-  // Returns the BatteryStatusService singleton.
-  static BatteryStatusService* GetInstance();
-
-  // Adds a callback to receive battery status updates.  Must be called on the
-  // main thread. The callback itself will be called on the main thread as well.
-  // NOTE: The callback may be run before AddCallback returns!
-  std::unique_ptr<BatteryUpdateSubscription> AddCallback(
-      const BatteryUpdateCallback& callback);
-
-  // Gracefully clean-up.
-  void Shutdown();
-
-  // Injects a custom battery status manager for testing purposes.
-  void SetBatteryManagerForTesting(
-      std::unique_ptr<BatteryStatusManager> test_battery_manager);
-
-  // Returns callback to invoke when battery is changed. Used for testing.
-  const BatteryUpdateCallback& GetUpdateCallbackForTesting() const;
-
- private:
-  friend struct base::DefaultSingletonTraits<BatteryStatusService>;
-  friend class BatteryStatusServiceTest;
-
-  BatteryStatusService();
-  virtual ~BatteryStatusService();
-
-  // Updates current battery status and sends new status to interested
-  // render processes. Can be called on any thread via a callback.
-  void NotifyConsumers(const mojom::BatteryStatus& status);
-  void NotifyConsumersOnMainThread(const mojom::BatteryStatus& status);
-  void ConsumersChanged();
-
-  scoped_refptr<base::SingleThreadTaskRunner> main_thread_task_runner_;
-  std::unique_ptr<BatteryStatusManager> battery_fetcher_;
-  BatteryUpdateCallbackList callback_list_;
-  BatteryUpdateCallback update_callback_;
-  mojom::BatteryStatus status_;
-  bool status_updated_;
-  bool is_shutdown_;
-
-  DISALLOW_COPY_AND_ASSIGN(BatteryStatusService);
-};
-
-}  // namespace device
-
-#endif  // DEVICE_BATTERY_BATTERY_STATUS_SERVICE_H_