Revert of Deletes mojo::Callback

device/battery/battery_monitor_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_BATTERY_BATTERY_MONITOR_IMPL_H_
 #define DEVICE_BATTERY_BATTERY_MONITOR_IMPL_H_
 
 #include <memory>
 
 #include "base/macros.h"
 #include "device/battery/battery_export.h"
 #include "device/battery/battery_monitor.mojom.h"
 #include "device/battery/battery_status_service.h"
 #include "mojo/public/cpp/bindings/strong_binding.h"
 
 namespace device {
 
 class BatteryMonitorImpl : public BatteryMonitor {
  public:
   DEVICE_BATTERY_EXPORT static void Create(
       mojo::InterfaceRequest<BatteryMonitor> request);
 
  private:
+  typedef mojo::Callback<void(BatteryStatusPtr)> BatteryStatusCallback;
+
   explicit BatteryMonitorImpl(mojo::InterfaceRequest<BatteryMonitor> request);
   ~BatteryMonitorImpl() override;
 
   // BatteryMonitor methods:
-  void QueryNextStatus(const QueryNextStatusCallback& callback) override;
+  void QueryNextStatus(const BatteryStatusCallback& callback) override;
 
   void RegisterSubscription();
   void DidChange(const BatteryStatus& battery_status);
   void ReportStatus();
 
   mojo::StrongBinding<BatteryMonitor> binding_;
   std::unique_ptr<BatteryStatusService::BatteryUpdateSubscription>
       subscription_;
-  QueryNextStatusCallback callback_;
+  BatteryStatusCallback callback_;
   BatteryStatus status_;
   bool status_to_report_;
 
   DISALLOW_COPY_AND_ASSIGN(BatteryMonitorImpl);
 };
 
 }  // namespace device
 
 #endif  // DEVICE_BATTERY_BATTERY_MONITOR_IMPL_H_