diff -r 000000000000 -r 6474c204b198 ipc/chromium/src/base/system_monitor.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/ipc/chromium/src/base/system_monitor.h	Wed Dec 31 06:09:35 2014 +0100
@@ -0,0 +1,129 @@
+// Copyright (c) 2008 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 BASE_SYSTEM_MONITOR_H_
+#define BASE_SYSTEM_MONITOR_H_
+
+#include "base/observer_list_threadsafe.h"
+#include "base/singleton.h"
+
+// Windows HiRes timers drain the battery faster so we need to know the battery
+// status.  This isn't true for other platforms.
+#if defined(OS_WIN)
+#define ENABLE_BATTERY_MONITORING 1
+#else
+#undef ENABLE_BATTERY_MONITORING
+#endif  // !OS_WIN
+
+namespace base {
+
+// Class for monitoring various system-related subsystems
+// such as power management, network status, etc.
+// TODO(mbelshe):  Add support beyond just power management.
+class SystemMonitor {
+ public:
+  // Access to the Singleton
+  static SystemMonitor* Get() {
+    // Uses the LeakySingletonTrait because cleanup is optional.
+    return
+        Singleton<SystemMonitor, LeakySingletonTraits<SystemMonitor> >::get();
+  }
+
+  // Start the System Monitor within a process.  This method
+  // is provided so that the battery check can be deferred.
+  // The MessageLoop must be started before calling this
+  // method.
+  // This is a no-op on platforms for which ENABLE_BATTERY_MONITORING is
+  // disabled.
+  static void Start();
+
+  //
+  // Power-related APIs
+  //
+
+  // Is the computer currently on battery power.
+  // Can be called on any thread.
+  bool BatteryPower() {
+    // Using a lock here is not necessary for just a bool.
+    return battery_in_use_;
+  }
+
+  // Normalized list of power events.
+  enum PowerEvent {
+    POWER_STATE_EVENT,  // The Power status of the system has changed.
+    SUSPEND_EVENT,      // The system is being suspended.
+    RESUME_EVENT        // The system is being resumed.
+  };
+
+  // Callbacks will be called on the thread which creates the SystemMonitor.
+  // During the callback, Add/RemoveObserver will block until the callbacks
+  // are finished. Observers should implement quick callback functions; if
+  // lengthy operations are needed, the observer should take care to invoke
+  // the operation on an appropriate thread.
+  class PowerObserver {
+  public:
+    // Notification of a change in power status of the computer, such
+    // as from switching between battery and A/C power.
+    virtual void OnPowerStateChange(SystemMonitor*) = 0;
+
+    // Notification that the system is suspending.
+    virtual void OnSuspend(SystemMonitor*) = 0;
+
+    // Notification that the system is resuming.
+    virtual void OnResume(SystemMonitor*) = 0;
+  };
+
+  // Add a new observer.
+  // Can be called from any thread.
+  // Must not be called from within a notification callback.
+  void AddObserver(PowerObserver* obs);
+
+  // Remove an existing observer.
+  // Can be called from any thread.
+  // Must not be called from within a notification callback.
+  void RemoveObserver(PowerObserver* obs);
+
+#if defined(OS_WIN)
+  // Windows-specific handling of a WM_POWERBROADCAST message.
+  // Embedders of this API should hook their top-level window
+  // message loop and forward WM_POWERBROADCAST through this call.
+  void ProcessWmPowerBroadcastMessage(int event_id);
+#endif
+
+  // Cross-platform handling of a power event.
+  void ProcessPowerMessage(PowerEvent event_id);
+
+  // Constructor.
+  // Don't use this; access SystemMonitor via the Singleton.
+  SystemMonitor();
+
+ private:
+  // Platform-specific method to check whether the system is currently
+  // running on battery power.  Returns true if running on batteries,
+  // false otherwise.
+  bool IsBatteryPower();
+
+  // Checks the battery status and notifies observers if the battery
+  // status has changed.
+  void BatteryCheck();
+
+  // Functions to trigger notifications.
+  void NotifyPowerStateChange();
+  void NotifySuspend();
+  void NotifyResume();
+
+  scoped_refptr<ObserverListThreadSafe<PowerObserver> > observer_list_;
+  bool battery_in_use_;
+  bool suspended_;
+
+#if defined(ENABLE_BATTERY_MONITORING)
+  base::OneShotTimer<SystemMonitor> delayed_battery_check_;
+#endif
+
+  DISALLOW_COPY_AND_ASSIGN(SystemMonitor);
+};
+
+}
+
+#endif  // BASE_SYSTEM_MONITOR_H_