Mojoify PoweMonitorMessageBroadcaster IPC from browser to child process

device/power_monitor/public/interfaces/power_monitor.mojom

+// Copyright 2016 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.
+
+module device.mojom;
+
+interface PowerMonitor {
+  // Set client that will be notified on PowerStateChange, Suspend and Resume.
+  SetClient(PowerMonitorClient client);
+};
+
+interface PowerMonitorClient {
+  // Notification of a change in power status of the computer, such
+  // as from switching between battery and A/C power.
+  PowerStateChange(bool on_battery_power);
+
+  // Notification that the system is suspending.
+  Suspend();
+
+  // Notification that the system is resuming.
+  Resume();
+};