Pass MSE media track info from ChunkDemuxer to blink::SourceBuffer

media/blink/websourcebuffer_impl.cc

Index: media/blink/websourcebuffer_impl.cc
diff --git a/media/blink/websourcebuffer_impl.cc b/media/blink/websourcebuffer_impl.cc
index 6b08b1319634b55179767637f8fcb2d0f5df12cd..b2a73216dd9c907e0791a587e90b07d6e97f5d86 100644
--- a/media/blink/websourcebuffer_impl.cc
+++ b/media/blink/websourcebuffer_impl.cc
@@ -15,6 +15,7 @@
 #include "media/base/media_tracks.h"
 #include "media/base/timestamp_constants.h"
 #include "media/filters/chunk_demuxer.h"
+#include "third_party/WebKit/public/platform/WebMediaPlayer.h"
 #include "third_party/WebKit/public/platform/WebSourceBufferClient.h"
 
 namespace media {
@@ -159,11 +160,33 @@ void WebSourceBufferImpl::removedFromMediaSource() {
   client_ = NULL;
 }
 
+blink::WebMediaPlayer::TrackType mediaTrackTypeToBlink(MediaTrack::Type type) {
+  switch (type) {
+    case MediaTrack::Audio:
+      return blink::WebMediaPlayer::AudioTrack;
+    case MediaTrack::Text:
+      return blink::WebMediaPlayer::TextTrack;
+    case MediaTrack::Video:
+      return blink::WebMediaPlayer::VideoTrack;
+  }
+  NOTREACHED();
+  return blink::WebMediaPlayer::AudioTrack;
+}
+
 void WebSourceBufferImpl::InitSegmentReceived(scoped_ptr<MediaTracks> tracks) {
   DVLOG(1) << __FUNCTION__;
-  // TODO(servolk): Implement passing MediaTrack info to blink level.
-  // https://crbug.com/249428
-  client_->initializationSegmentReceived();
+  blink::WebVector<blink::WebMediaPlayer::TrackId> blinkTrackIds(

[wolenetz, 2016/03/23 19:34:12]

nit: DCHECK_LT(0, tracks->tracks().size() ?

[servolk, 2016/03/24 01:31:55]

No need for this dcheck here, since the case of empty media tracks set is
explicitly called out in MSE spec and handled in
client_->initializationSegmentReceived (see step 2 at
https://www.w3.org/TR/media-source/#sourcebuffer-init-segment-received).

[wolenetz, 2016/03/24 01:54:06]

Acknowledged.

+      tracks->tracks().size());
+  size_t i = 0;
+  for (const auto& track : tracks->tracks()) {
+    blinkTrackIds[i++] = client_->createMediaTrack(

[wolenetz, 2016/03/23 19:34:13]

Are these blinkTrackIds only valid within the processing of the pendingTracks in
blink? Or does Chromium need to know these at some point, too?

[servolk, 2016/03/24 01:31:55]

Chromium does need to know these, since media track status changes are reported
by blink through giving us a set of blink track ids. So we need to be able to
map those track ids to our internal objects (MediaTrack or DemuxerStream), see
https://codereview.chromium.org/1812543003/ for an example of how that could be
done.

[wolenetz, 2016/03/24 01:54:07]

Acknowledged.

+        mediaTrackTypeToBlink(track->type()),
+        blink::WebString::fromUTF8(track->id()),
+        blink::WebString::fromUTF8(track->kind()),
+        blink::WebString::fromUTF8(track->label()),
+        blink::WebString::fromUTF8(track->language()));
+  }
+  client_->initializationSegmentReceived(blinkTrackIds);
 }
 
 }  // namespace media