support video device enumeration from renderer process.

content/browser/renderer_host/media/media_stream_device_settings.h

Index: content/browser/renderer_host/media/media_stream_device_settings.h
===================================================================
--- content/browser/renderer_host/media/media_stream_device_settings.h	(revision 118766)
+++ content/browser/renderer_host/media/media_stream_device_settings.h	(working copy)
@@ -51,8 +51,8 @@
                                  const StreamOptions& stream_components,
                                  const std::string& security_origin);
 
-  // Called as response to SettingsRequester::GetDevices. One response for each
-  // call to |GetDevices| is expected.
+  // Called to pass in an array of available devices for a request represented
+  // by |label|. There could be multiple calls for a request.
   void AvailableDevices(const std::string& label, MediaStreamType stream_type,
                         const StreamDeviceInfoArray& devices);