Revert 109960 - Send WM_DEVICECHANGE message through SystemMonitor

base/system_monitor/system_monitor.h

Index: base/system_monitor/system_monitor.h
===================================================================
--- base/system_monitor/system_monitor.h	(revision 109978)
+++ base/system_monitor/system_monitor.h	(working copy)
@@ -90,26 +90,15 @@
     virtual ~PowerObserver() {}
   };
 
-  class BASE_EXPORT DevicesChangedObserver {
-   public:
-    // Notification that the devices connected to the system have changed.
-    virtual void OnDevicesChanged() {}
-
-   protected:
-    virtual ~DevicesChangedObserver() {}
-  };
-
   // Add a new observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
-  void AddPowerObserver(PowerObserver* obs);
-  void AddDevicesChangedObserver(DevicesChangedObserver* obs);
+  void AddObserver(PowerObserver* obs);
 
   // Remove an existing observer.
   // Can be called from any thread.
   // Must not be called from within a notification callback.
-  void RemovePowerObserver(PowerObserver* obs);
-  void RemoveDevicesChangedObserver(DevicesChangedObserver* obs);
+  void RemoveObserver(PowerObserver* obs);
 
 #if defined(OS_WIN)
   // Windows-specific handling of a WM_POWERBROADCAST message.
@@ -121,9 +110,6 @@
   // Cross-platform handling of a power event.
   void ProcessPowerMessage(PowerEvent event_id);
 
-  // Cross-platform handling of a device change event.
-  void ProcessDevicesChanged();
-
  private:
 #if defined(OS_MACOSX)
   void PlatformInit();
@@ -140,14 +126,11 @@
   void BatteryCheck();
 
   // Functions to trigger notifications.
-  void NotifyDevicesChanged();
   void NotifyPowerStateChange();
   void NotifySuspend();
   void NotifyResume();
 
-  scoped_refptr<ObserverListThreadSafe<PowerObserver> > power_observer_list_;
-  scoped_refptr<ObserverListThreadSafe<DevicesChangedObserver> >
-      devices_changed_observer_list_;
+  scoped_refptr<ObserverListThreadSafe<PowerObserver> > observer_list_;
   bool battery_in_use_;
   bool suspended_;