Revert 109960 - Send WM_DEVICECHANGE message through SystemMonitor

base/system_monitor/system_monitor.cc

Index: base/system_monitor/system_monitor.cc
===================================================================
--- base/system_monitor/system_monitor.cc	(revision 109978)
+++ base/system_monitor/system_monitor.cc	(working copy)
@@ -19,9 +19,7 @@
 #endif  // defined(ENABLE_BATTERY_MONITORING)
 
 SystemMonitor::SystemMonitor()
-    : power_observer_list_(new ObserverListThreadSafe<PowerObserver>()),
-      devices_changed_observer_list_(
-          new ObserverListThreadSafe<DevicesChangedObserver>()),
+    : observer_list_(new ObserverListThreadSafe<PowerObserver>()),
       battery_in_use_(false),
       suspended_(false) {
   DCHECK(!g_system_monitor);
@@ -79,47 +77,28 @@
   }
 }
 
-void SystemMonitor::ProcessDevicesChanged() {
-  NotifyDevicesChanged();
+void SystemMonitor::AddObserver(PowerObserver* obs) {
+  observer_list_->AddObserver(obs);
 }
 
-void SystemMonitor::AddPowerObserver(PowerObserver* obs) {
-  power_observer_list_->AddObserver(obs);
+void SystemMonitor::RemoveObserver(PowerObserver* obs) {
+  observer_list_->RemoveObserver(obs);
 }
 
-void SystemMonitor::RemovePowerObserver(PowerObserver* obs) {
-  power_observer_list_->RemoveObserver(obs);
-}
-
-void SystemMonitor::AddDevicesChangedObserver(DevicesChangedObserver* obs) {
-  devices_changed_observer_list_->AddObserver(obs);
-}
-
-void SystemMonitor::RemoveDevicesChangedObserver(DevicesChangedObserver* obs) {
-  devices_changed_observer_list_->RemoveObserver(obs);
-}
-
-void SystemMonitor::NotifyDevicesChanged() {
-  DVLOG(1) << "DevicesChanged";
-  devices_changed_observer_list_->Notify(
-    &DevicesChangedObserver::OnDevicesChanged);
-}
-
 void SystemMonitor::NotifyPowerStateChange() {
   DVLOG(1) << "PowerStateChange: " << (BatteryPower() ? "On" : "Off")
            << " battery";
-  power_observer_list_->Notify(&PowerObserver::OnPowerStateChange,
-                               BatteryPower());
+  observer_list_->Notify(&PowerObserver::OnPowerStateChange, BatteryPower());
 }
 
 void SystemMonitor::NotifySuspend() {
   DVLOG(1) << "Power Suspending";
-  power_observer_list_->Notify(&PowerObserver::OnSuspend);
+  observer_list_->Notify(&PowerObserver::OnSuspend);
 }
 
 void SystemMonitor::NotifyResume() {
   DVLOG(1) << "Power Resuming";
-  power_observer_list_->Notify(&PowerObserver::OnResume);
+  observer_list_->Notify(&PowerObserver::OnResume);
 }
 
 void SystemMonitor::BatteryCheck() {