Revert 109960 - Send WM_DEVICECHANGE message through SystemMonitor

WM_DEVICECHANGE is sent when there's been a change to devices or the computer;
specifically when a USB device is connected or disconnected. This is intended
for use in support of Gamepads for more performant polling and
connect/disconnect testing. Currently only on Windows, though seems reasonable
to add for other platforms in the future.

BUG=79050


Review URL: http://codereview.chromium.org/8523021

TBR=scottmg@chromium.org
Review URL: http://codereview.chromium.org/8528044

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@109979 0039d316-1c4b-4281-b951-d872f2087c98

3 files changed, 12 insertions, 95 deletions

diff --git a/base/system_monitor/system_monitor.cc b/base/system_monitor/system_monitor.cc
index 28fc70b..5131fbf 100644
--- a/base/system_monitor/system_monitor.cc
+++ b/base/system_monitor/system_monitor.cc
@@ -19,9 +19,7 @@ static int kDelayedBatteryCheckMs = 10 * 1000;
 #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::ProcessPowerMessage(PowerEvent event_id) {
   }
 }
 
-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::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::RemoveObserver(PowerObserver* obs) {
+  observer_list_->RemoveObserver(obs);
 }
 
 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() {
diff --git a/base/system_monitor/system_monitor.h b/base/system_monitor/system_monitor.h
index 7684523..c779994 100644
--- a/base/system_monitor/system_monitor.h
+++ b/base/system_monitor/system_monitor.h
@@ -90,26 +90,15 @@ class BASE_EXPORT SystemMonitor {
     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 @@ class BASE_EXPORT SystemMonitor {
   // 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 @@ class BASE_EXPORT SystemMonitor {
   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_;
 
diff --git a/base/system_monitor/system_monitor_unittest.cc b/base/system_monitor/system_monitor_unittest.cc
index 1d5d6af..f4a4e73 100644
--- a/base/system_monitor/system_monitor_unittest.cc
+++ b/base/system_monitor/system_monitor_unittest.cc
@@ -55,7 +55,7 @@ TEST(SystemMonitor, PowerNotifications) {
   SystemMonitor system_monitor;
   PowerTest test[kObservers];
   for (int index = 0; index < kObservers; ++index)
-    system_monitor.AddPowerObserver(&test[index]);
+    system_monitor.AddObserver(&test[index]);
 
   // Send a bunch of power changes.  Since the battery power hasn't
   // actually changed, we shouldn't get notifications.
@@ -90,49 +90,4 @@ TEST(SystemMonitor, PowerNotifications) {
   EXPECT_EQ(test[0].resumes(), 1);
 }
 
-class DevicesChangedTest : public SystemMonitor::DevicesChangedObserver {
- public:
-  DevicesChangedTest()
-      : changes_(0) {
-  }
-
-  // DevicesChangedObserver callbacks.
-  virtual void OnDevicesChanged() OVERRIDE {
-    changes_++;
-  }
-
-  // Test status counts.
-  int changes() const { return changes_; }
-
- private:
-  int changes_;  // Count of OnDevicesChanged notifications.
-
-  DISALLOW_COPY_AND_ASSIGN(DevicesChangedTest);
-};
-
-TEST(SystemMonitor, DeviceChangeNotifications) {
-  const int kObservers = 5;
-
-  // Initialize a message loop for this to run on.
-  MessageLoop loop;
-
-#if defined(OS_MACOSX)
-  SystemMonitor::AllocateSystemIOPorts();
-#endif
-
-  SystemMonitor system_monitor;
-  DevicesChangedTest test[kObservers];
-  for (int index = 0; index < kObservers; ++index)
-    system_monitor.AddDevicesChangedObserver(&test[index]);
-
-  system_monitor.ProcessDevicesChanged();
-  loop.RunAllPending();
-  EXPECT_EQ(1, test[0].changes());
-
-  system_monitor.ProcessDevicesChanged();
-  system_monitor.ProcessDevicesChanged();
-  loop.RunAllPending();
-  EXPECT_EQ(3, test[0].changes());
-}
-
 }  // namespace base