Define EncodedVideoSource and RtcCapturedEncodingVideoCapturer.

media/video/capture/video_capture.h

Index: media/video/capture/video_capture.h
diff --git a/media/video/capture/video_capture.h b/media/video/capture/video_capture.h
index a63843e4742c9baaa55dd109d003f33dda41c5f7..6d0ce2a5b4d46eedb49b07670d165170c44b0502 100644
--- a/media/video/capture/video_capture.h
+++ b/media/video/capture/video_capture.h
@@ -16,6 +16,8 @@
 
 namespace media {
 
+class EncodedVideoSource;
+
 class MEDIA_EXPORT VideoCapture {
  public:
   // TODO(wjia): consider merging with media::VideoFrame if possible.
@@ -96,6 +98,13 @@ class MEDIA_EXPORT VideoCapture {
   virtual int CaptureHeight() = 0;
   virtual int CaptureFrameRate() = 0;
 
+  // Tells the client whether platform and camera has encoding support.
+  // The operation of encoder is tied to capture controlled by the functions
+  // of VideoCapture interface. E.g. calling VideoCapture::StopCapture() will
+  // also stop the streaming of encoded streams.

[Ami GONE FROM CHROMIUM, 2013/06/08 00:18:01]

This is not enough information.  For example it implies one still calls
VideoCapture::StartCapture() to start getting encoded bitstreambuffers, but it
doesn't say what to pass for a  the |handler| param to StartCapture.  It sort of
implies that raw frames will be returned to the handler while
encodedbitstreambuffers will be returned to the EVS::Client registered with
Initialize.

[hshi1, 2013/06/11 17:49:42]

I realized it is completely unnecessary to change this header at all. I'm
reverting it. There is no reason to add this method in the VideoCapture
interface. The base VideoCapture interface will always have no encoding
capabilities. This way I don't have to deal with pepper video capture either.

+  // All platforms or cameras may have not encoding support available.

[Ami GONE FROM CHROMIUM, 2013/06/08 00:18:01]

Comment is written as if this returns a bool, not a pointer.

[Ami GONE FROM CHROMIUM, 2013/06/08 00:18:01]

If this was impl'd to return NULL (in a new video_capture.cc file) then you
wouldn't need to propagate this as a do-nothing to
pepper_platform_video_capture_impl.cc and so on.

(there's no value to this being a pure abstract class)

[hshi1, 2013/06/11 17:49:42]

N/A (file reverted).

[hshi1, 2013/06/11 17:49:42]

N/A (file reverted).

+  virtual EncodedVideoSource* GetEncodedVideoSource() = 0;

[Ami GONE FROM CHROMIUM, 2013/06/08 00:18:01]

What are the ownership semantics of the returned pointer?

[hshi1, 2013/06/11 17:49:42]

N/A (file reverted).

+
  protected:
   virtual ~VideoCapture() {}