support video device enumeration from renderer process.

content/browser/renderer_host/media/media_stream_dispatcher_host.h

Index: content/browser/renderer_host/media/media_stream_dispatcher_host.h
===================================================================
--- content/browser/renderer_host/media/media_stream_dispatcher_host.h	(revision 111389)
+++ content/browser/renderer_host/media/media_stream_dispatcher_host.h	(working copy)
@@ -42,6 +42,13 @@
   virtual void AudioDeviceFailed(const std::string& label, int index) OVERRIDE;
   virtual void VideoDeviceFailed(const std::string& label, int index) OVERRIDE;
 
+  virtual void VideoDevicesEnumerated(const std::string& label,
+                                      const StreamDeviceInfoArray& devices);
+  virtual void VideoDevicesEnumerationFailed(const std::string& label);
+  virtual void VideoDeviceOpened(const std::string& label,

[mflodman_chromium_OOO, 2011/11/29 02:30:56]

Q: Since we'll support audio in the future(?), what do you think about naming
this DeviceOpened and add MediaStreamType as a parameter?
Same for the calls below, IPC messages and MediaStreamManager.

[wjia(left Chromium), 2011/11/30 00:14:23]

Done. I thought the first step is to make video work. Then expand it to audio.
Since you are asking, these two steps are merged.

+                                 const StreamDeviceInfo& video_device);
+  virtual void VideoDeviceOpenFailed(const std::string& label);
+
   // BrowserMessageFilter implementation.
   virtual bool OnMessageReceived(const IPC::Message& message,
                                  bool* message_was_ok) OVERRIDE;
@@ -57,6 +64,15 @@
 
   void OnStopGeneratedStream(int render_view_id, const std::string& label);
 
+  void OnEnumerateVideoDevices(int render_view_id,
+                               int page_request_id,
+                               const std::string& security_origin);
+
+  void OnOpenVideoDevice(int render_view_id,
+                         int page_request_id,
+                         const std::string& device_id,
+                         const std::string& security_origin);
+
   // Returns the media stream manager to forward events to,
   // creating one if needed.
   MediaStreamManager* manager();