Add Media device notification to SystemMonitor and Mac impl

base/system_monitor/system_monitor.cc

Index: base/system_monitor/system_monitor.cc
diff --git a/base/system_monitor/system_monitor.cc b/base/system_monitor/system_monitor.cc
index 28fc70bf2b42a1dd21dc04880ac17efec4ea55ab..f3254d009d90c5b79c43e36bd2f7058fe86719e9 100644
--- a/base/system_monitor/system_monitor.cc
+++ b/base/system_monitor/system_monitor.cc
@@ -83,6 +83,17 @@ void SystemMonitor::ProcessDevicesChanged() {
   NotifyDevicesChanged();
 }
 
+void SystemMonitor::ProcessMediaDeviceAttached(const std::string& name,
+                                               const FilePath& path) {
+  NotifyDevicesChanged();

[tpayne, 2012/02/08 16:20:30]

At least on windows, this will end up getting called twice because windows
generates 2 separate events for attach/detach.

[vandebo (ex-Chrome), 2012/02/08 18:37:01]

Yea, I realized that on my drive home.  Maybe we should make DeviceChanged more
specific - is it only USB devices that trigger it now?

+  NotifyMediaDeviceAttached(name, path);
+}
+
+void SystemMonitor::ProcessMediaDeviceDetached(const std::string& name) {
+  NotifyDevicesChanged();
+  NotifyMediaDeviceDetached(name);
+}
+
 void SystemMonitor::AddPowerObserver(PowerObserver* obs) {
   power_observer_list_->AddObserver(obs);
 }
@@ -105,6 +116,17 @@ void SystemMonitor::NotifyDevicesChanged() {
     &DevicesChangedObserver::OnDevicesChanged);
 }
 
+void SystemMonitor::NotifyMediaDeviceAttached(const std::string& name,
+                                              const FilePath& path) {
+  devices_changed_observer_list_->Notify(
+    &DevicesChangedObserver::OnMediaDeviceAttached, name, path);
+}
+
+void SystemMonitor::NotifyMediaDeviceDetached(const std::string& name) {
+  devices_changed_observer_list_->Notify(
+    &DevicesChangedObserver::OnMediaDeviceDetached, name);
+}
+
 void SystemMonitor::NotifyPowerStateChange() {
   DVLOG(1) << "PowerStateChange: " << (BatteryPower() ? "On" : "Off")
            << " battery";