Implements MediaStreamVideoSource.

content/renderer/media/media_stream_video_source.cc

Index: content/renderer/media/media_stream_video_source.cc
diff --git a/content/renderer/media/media_stream_video_source.cc b/content/renderer/media/media_stream_video_source.cc
index acdb7dfc9012677655a044d41e43688d08d1cde3..c0d9f956fd8e4026c4aa28d36a9cdf1b5642ae25 100644
--- a/content/renderer/media/media_stream_video_source.cc
+++ b/content/renderer/media/media_stream_video_source.cc
@@ -5,21 +5,58 @@
 #include "content/renderer/media/media_stream_video_source.h"
 
 #include "base/logging.h"
-#include "content/public/renderer/media_stream_video_sink.h"
+#include "content/renderer/media/media_stream_dependency_factory.h"
+#include "content/renderer/media/media_stream_source_extra_data.h"
+#include "content/renderer/render_thread_impl.h"
+#include "third_party/WebKit/public/platform/WebMediaStreamSource.h"
+#include "third_party/libjingle/source/talk/app/webrtc/remotevideocapturer.h"
+#include "third_party/libjingle/source/talk/media/webrtc/webrtcvideoframe.h"
 
 namespace content {
 
-void MediaStreamVideoSource::AddTrack(
+MediaStreamVideoSource::MediaStreamVideoSource(
+    MediaStreamDependencyFactory* factory)
+    : factory_(factory),
+      width_(0),
+      height_(0) {
+}
+
+bool MediaStreamVideoSource::Init() {
+  if (!factory_) {

[perkj_chrome, 2014/01/10 13:07:00]

You might want to use dependency injection of the factory in order to be able to
write a unit test that use the mock factory.

Please also see my CL MediaStreamVideoCaptureDeviceSource. I suggest you create
a new source that inherits from MediaStreamVideoSource and have Init on that
method. 

The only difference between the two implementations at the moment would be that
you create a webrtc::RemoteVideoCapturer instead of a RTCVideoCapturer.

[Ronghua Wu (Left Chromium), 2014/01/11 01:22:58]

I do have the injection, see the ctor.

Regarding to the RTCVideoCapturer, I had some comments in your cl. Basically I'm
trying to hide the libjingle detail inside the MediaStreamVideoSource. The
derived class of MediaStreamVideoSource should only use DeliverVideoFrame
interface instead of injecting a VideoSourceInterface.

The base class on the other hand, always uses the fake capturer just to fulfill
the need of the webrtcvideoengine, so that chromium code doesn't need to use
cricket::VideoCapturer anywhere else.

+    factory_ = RenderThreadImpl::current()->GetMediaStreamDependencyFactory();
+    DCHECK(factory_ != NULL);
+  }
+  blink::WebMediaConstraints constraints;
+  adapter_ = factory_->CreateVideoSource(
+      new webrtc::RemoteVideoCapturer(), constraints);
+  return true;
+}
+
+bool MediaStreamVideoSource::AddTrack(
     const blink::WebMediaStreamTrack& track,
     const blink::WebMediaConstraints& constraints) {
-  // TODO(ronghuawu): Put |track| in the registered tracks list. Will later
-  // deliver frames to it according to |constraints|.
+  // WebMediaStreamTrack init requires WebMediaStreamSource, so assuming it's
+  // not null at this point.
+  if (track.isNull() || track.source().isNull()) {
+    return false;
+  }
+  blink::WebMediaStreamSource source = track.source();

[perkj_chrome, 2014/01/10 13:07:00]

This seem wrong. The source already has extra data and just because you add a
new track you can not create an extra data field.

Actually - if you look at my cl https://codereview.chromium.org/131763002/- you
will see that you don't need to implement this at all at the moment. 
Just continue to let the webrtc track add itself to the webrtc video source
interface.

[Ronghua Wu (Left Chromium), 2014/01/11 01:22:58]

The idea is before a track is add/associated with a source, there should be no
source for the track. For example the track created using the new
MediaStreamDependencyFactory::CreateMediaStreamVideoTrack.

+  if (source.extraData()) {
+    // The track has already associated with a native source.
+    return false;
+  }
+  MediaStreamSourceExtraData* source_data = new MediaStreamSourceExtraData();
+  source_data->SetVideoSource(adapter_.get());
+  source.setExtraData(source_data);
+
+  factory_->CreateNativeMediaStreamTrack(track);
+  return true;
 }
 
-void MediaStreamVideoSource::RemoveTrack(
+bool MediaStreamVideoSource::RemoveTrack(
     const blink::WebMediaStreamTrack& track) {
-  // TODO(ronghuawu): Remove |track| from the list, i.e. will stop delivering
-  // frame to |track|.
+  // TODO(ronghuawu): What can be done here? Do we need RemoveTrack or how?

[perkj_chrome, 2014/01/10 13:07:00]

This means that a track is being destroyed by webkit and that the source should
no longer provide data to it.

Since we still use the webrtc way and you don't store a reference from the
source to the track- you can just do nothing at the time. 

[Ronghua Wu (Left Chromium), 2014/01/11 01:22:58]

Ack

+  return true;
 }
 
 void MediaStreamVideoSource::SetReadyState(
@@ -30,7 +67,19 @@ void MediaStreamVideoSource::SetReadyState(
 
 void MediaStreamVideoSource::DeliverVideoFrame(
     const scoped_refptr<media::VideoFrame>& frame) {
-  // TODO(ronghuawu): Deliver |frame| to all the registered tracks.
+  cricket::VideoRenderer* input = adapter_->FrameInput();
+
+  if (width_ != frame->coded_size().width() ||
+      height_ != frame->coded_size().height()) {
+    width_ = frame->coded_size().width();
+    height_ = frame->coded_size().height();
+    const int reserved = 0;
+    input->SetSize(width_, height_, reserved);
+  }
+
+  cricket::WebRtcVideoFrame cricket_frame;
+  // TODO(ronghuawu): convert from media::VideoFrame to cricket::VideoFrame.

[perkj_chrome, 2014/01/10 13:07:00]

Take a look at RTCVideoCapture to see how we convert at the moment. 

+  input->RenderFrame(&cricket_frame);
 }
 
 MediaStreamVideoSource::~MediaStreamVideoSource() {