Created multi-process-friendly PowerMonitor interface.

base/power_monitor/power_monitor_source.cc

+// Copyright 2013 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 "base/power_monitor/power_monitor_source.h"
+
+#include "base/power_monitor/power_monitor.h"
+
+namespace base {
+
+PowerMonitorSource::PowerMonitorSource()
+    : battery_in_use_(false),
+      suspended_(false) {
+}
+
+PowerMonitorSource::~PowerMonitorSource() {
+}
+
+bool PowerMonitorSource::BatteryPower() {
+  AutoLock auto_lock(lock_);
+  return battery_in_use_;
+}
+
+bool PowerMonitorSource::IsBatteryPower() {

[palmer, 2013/07/09 21:16:10]

This is a very strange wart.

+  NOTIMPLEMENTED();
+  return false;
+}
+
+void PowerMonitorSource::ProcessPowerEvent(PowerEvent event_id) {
+  PowerMonitor* monitor = PowerMonitor::Get();
+
+  // Suppress duplicate notifications.  Some platforms may
+  // send multiple notifications of the same event.
+  switch (event_id) {
+    case POWER_STATE_EVENT:
+      {
+        bool on_battery = IsBatteryPower();

[palmer, 2013/07/09 21:16:10]

This will trigger NOTIMPLEMENTED.

+        if (on_battery != battery_in_use_) {
+          lock_.Acquire();
+          battery_in_use_ = on_battery;
+          lock_.Release();
+          if (monitor)
+            monitor->NotifyPowerStateChange(on_battery);
+        }
+      }
+      break;
+    case RESUME_EVENT:
+      if (suspended_) {
+        suspended_ = false;
+        if (monitor)
+          monitor->NotifyResume();
+      }
+      break;
+    case SUSPEND_EVENT:
+      if (!suspended_) {
+        suspended_ = true;
+        if (monitor)
+          monitor->NotifySuspend();
+      }
+      break;
+  }
+}
+
+}  // namespace base