Created multi-process-friendly PowerMonitor interface.

base/power_monitor/power_monitor_device_source.h

 // 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.
 
-#ifndef BASE_POWER_MONITOR_POWER_MONITOR_H_
-#define BASE_POWER_MONITOR_POWER_MONITOR_H_
+#ifndef BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_
+#define BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_
 
 #include "base/base_export.h"
 #include "base/basictypes.h"
 #include "base/memory/ref_counted.h"
 #include "base/observer_list_threadsafe.h"
+#include "base/power_monitor/power_monitor_source.h"
 #include "base/power_monitor/power_observer.h"
 
 #if defined(OS_WIN)
 #include <windows.h>
 
 // Windows HiRes timers drain the battery faster so we need to know the battery
 // status.  This isn't true for other platforms.
 #define ENABLE_BATTERY_MONITORING 1
 #else
 #undef ENABLE_BATTERY_MONITORING
 #endif  // !OS_WIN
 
 #if defined(ENABLE_BATTERY_MONITORING)
 #include "base/timer/timer.h"
 #endif  // defined(ENABLE_BATTERY_MONITORING)
 
 #if defined(OS_IOS)
 #include <objc/runtime.h>
 #endif  // OS_IOS
 
 namespace base {
 
 // A class used to monitor the power state change and notify the observers about
 // the change event.
-class BASE_EXPORT PowerMonitor {
+class BASE_EXPORT PowerMonitorDeviceSource : public PowerMonitorSource {
  public:
-  // 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.
-  };
-
-  PowerMonitor();
-  ~PowerMonitor();
-
-  // Get the application-wide PowerMonitor (if not present, returns NULL).
-  static PowerMonitor* Get();
+  PowerMonitorDeviceSource();
+  virtual ~PowerMonitorDeviceSource();
 
 #if defined(OS_MACOSX)
   // Allocate system resources needed by the PowerMonitor class.
   //
   // This function must be called before instantiating an instance of the class
   // and before the Sandbox is initialized.
 #if !defined(OS_IOS)
   static void AllocateSystemIOPorts();
 #else
   static void AllocateSystemIOPorts() {}
 #endif  // OS_IOS
 #endif  // OS_MACOSX
 
-  // Add and remove an observer.
-  // Can be called from any thread.
-  // Must not be called from within a notification callback.
-  void AddObserver(PowerObserver* observer);
-  void RemoveObserver(PowerObserver* observer);
-
-  // Is the computer currently on battery power. Can be called on any thread.
-  bool BatteryPower() const {
-    // Using a lock here is not necessary for just a bool.
-    return battery_in_use_;
-  }
-
  private:
-  friend class PowerMonitorTest;
-  // A friend function that is allowed to access the private ProcessPowerEvent.
-  friend void ProcessPowerEventHelper(PowerEvent);
-
 #if defined(OS_WIN)
   // Represents a message-only window for power message handling on Windows.
   // Only allow PowerMonitor to create it.
   class PowerMessageWindow {
    public:
     PowerMessageWindow();
     ~PowerMessageWindow();
 
    private:
     void ProcessWmPowerBroadcastMessage(int event_id);
     LRESULT CALLBACK WndProc(HWND hwnd, UINT message,
                              WPARAM wparam, LPARAM lparam);
     static LRESULT CALLBACK WndProcThunk(HWND hwnd,
                                          UINT message,
                                          WPARAM wparam,
                                          LPARAM lparam);
     // Instance of the module containing the window procedure.
     HMODULE instance_;
     // A hidden message-only window.
     HWND message_hwnd_;
   };
 #endif  // OS_WIN
 
 #if defined(OS_MACOSX)
   void PlatformInit();
   void PlatformDestroy();
 #endif
 
-  // Cross-platform handling of a power event.
-  void ProcessPowerEvent(PowerEvent event_id);
-
   // Platform-specific method to check whether the system is currently
   // running on battery power.  Returns true if running on batteries,
   // false otherwise.
-  bool IsBatteryPower();
+  virtual bool IsBatteryPower() OVERRIDE;

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

Harmonize this name with whatever you choose for the |BatteryPower| method in
the other file. I like |IsOnBatteryPower| (or maybe |IsUsingBatteryPower|) best,
but |IsBatteryPower| is fine, too.

 
   // Checks the battery status and notifies observers if the battery
   // status has changed.
   void BatteryCheck();
 
-  void NotifyPowerStateChange();
-  void NotifySuspend();
-  void NotifyResume();
-
 #if defined(OS_IOS)
   // Holds pointers to system event notification observers.
   std::vector<id> notification_observers_;
 #endif
 
 #if defined(ENABLE_BATTERY_MONITORING)
-  base::OneShotTimer<PowerMonitor> delayed_battery_check_;
+  base::OneShotTimer<PowerMonitorDeviceSource> delayed_battery_check_;
 #endif
 
-  scoped_refptr<ObserverListThreadSafe<PowerObserver> > observers_;
-  bool battery_in_use_;
-  bool suspended_;
-
 #if defined(OS_WIN)
   PowerMessageWindow power_message_window_;
 #endif
 
-  DISALLOW_COPY_AND_ASSIGN(PowerMonitor);
+  DISALLOW_COPY_AND_ASSIGN(PowerMonitorDeviceSource);
 };
 
 }  // namespace base
 
-#endif  // BASE_POWER_MONITOR_POWER_MONITOR_H_
+#endif  // BASE_POWER_MONITOR_POWER_MONITOR_DEVICE_SOURCE_H_