[DeviceService] Expose battery monitoring solely via the Device Service

device/battery/battery_monitor_impl.cc

-// 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.
-
-#include "device/battery/battery_monitor_impl.h"
-
-#include <utility>
-
-#include "base/bind.h"
-#include "base/logging.h"
-#include "base/memory/ptr_util.h"
-#include "mojo/public/cpp/bindings/strong_binding.h"
-
-namespace device {
-
-// static
-void BatteryMonitorImpl::Create(mojom::BatteryMonitorRequest request) {
-  auto* impl = new BatteryMonitorImpl;
-  auto binding =
-      mojo::MakeStrongBinding(base::WrapUnique(impl), std::move(request));
-  impl->binding_ = binding;
-}
-
-BatteryMonitorImpl::BatteryMonitorImpl() : status_to_report_(false) {
-  // NOTE: DidChange may be called before AddCallback returns. This is done to
-  // report current status.
-  subscription_ = BatteryStatusService::GetInstance()->AddCallback(
-      base::Bind(&BatteryMonitorImpl::DidChange, base::Unretained(this)));
-}
-
-BatteryMonitorImpl::~BatteryMonitorImpl() {
-}
-
-void BatteryMonitorImpl::QueryNextStatus(
-    const QueryNextStatusCallback& callback) {
-  if (!callback_.is_null()) {
-    DVLOG(1) << "Overlapped call to QueryNextStatus!";
-    binding_->Close();
-    return;
-  }
-  callback_ = callback;
-
-  if (status_to_report_)
-    ReportStatus();
-}
-
-void BatteryMonitorImpl::RegisterSubscription() {
-}
-
-void BatteryMonitorImpl::DidChange(const mojom::BatteryStatus& battery_status) {
-  status_ = battery_status;
-  status_to_report_ = true;
-
-  if (!callback_.is_null())
-    ReportStatus();
-}
-
-void BatteryMonitorImpl::ReportStatus() {
-  callback_.Run(status_.Clone());
-  callback_.Reset();
-
-  status_to_report_ = false;
-}
-
-}  // namespace device