Added AVFoundation Glue and Device Monitoring for Mac.

content/browser/device_monitor_mac.h

Index: content/browser/device_monitor_mac.h
diff --git a/content/browser/device_monitor_mac.h b/content/browser/device_monitor_mac.h
index bab522f4dbe5b5930e57fcacae1df370aaf03857..192caedea619dfd1d18a70f09226a0a4d78492c6 100644
--- a/content/browser/device_monitor_mac.h
+++ b/content/browser/device_monitor_mac.h
@@ -8,19 +8,28 @@
 #include "base/basictypes.h"
 #include "base/system_monitor/system_monitor.h"
 
+namespace {
+class MacMonitor;
+}
+
 namespace content {
 
+// Class to track audio/video devices removal or addition via callback to
+// base::SystemMonitor ProcessDevicesChanged(). From this class only a
+// singleton object is created that lasts as long as the browser process.

[Robert Sesek, 2013/10/16 23:58:07]

I don't really understand what this is getting at. I don't see base::Singleton
here.

[mcasas, 2013/10/17 08:16:36]

Perhaps I used the naming a bit too freely.

What I meant is that there's just one object of DeviceMonitorMac class, at once,
per browser process. It's instantiated from browser_main_loop.cc [1]. I will
rewrite for more clarity.

[1]
https://code.google.com/p/chromium/codesearch#chromium/src/content/browser/br...

 class DeviceMonitorMac {
  public:
   DeviceMonitorMac();
   ~DeviceMonitorMac();
 
- private:
-  // Forward the notifications to system monitor.
+  // Method called by the internal MacMonitor object |device_monitor_impl_| when
+  // a device of type |type| has been added to or removed from the system. This
+  // code executes in the notification thread (QTKit or AVFoundation).
   void NotifyDeviceChanged(base::SystemMonitor::DeviceType type);
 
-  class QTMonitorImpl;
-  scoped_ptr<DeviceMonitorMac::QTMonitorImpl> qt_monitor_;
+ private:
+  scoped_ptr<MacMonitor> device_monitor_impl_;
+
   DISALLOW_COPY_AND_ASSIGN(DeviceMonitorMac);
 };