Add SourceBuffer implementations of Audio/VideoTracks

third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp

Index: third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
diff --git a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
index 2fa35646b2d85e978b8d00c90306c75a62c097f0..871c54082a76a2b0f8c2a68a1d071f950e80c3a4 100644
--- a/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
+++ b/third_party/WebKit/Source/modules/mediasource/SourceBuffer.cpp
@@ -49,6 +49,7 @@
 #include "core/html/track/VideoTrackList.h"
 #include "core/streams/Stream.h"
 #include "modules/mediasource/MediaSource.h"
+#include "modules/mediasource/SourceBufferTrackBaseSupplement.h"
 #include "platform/Logging.h"
 #include "platform/TraceEvent.h"
 #include "public/platform/WebSourceBuffer.h"
@@ -232,6 +233,18 @@ void SourceBuffer::setTimestampOffset(double offset, ExceptionState& exceptionSt
     m_timestampOffset = offset;
 }
 
+AudioTrackList& SourceBuffer::audioTracks()
+{
+    ASSERT(RuntimeEnabledFeatures::audioVideoTracksEnabled());
+    return *m_audioTracks;

[wolenetz, 2016/03/23 20:18:52]

Prior to attachment of MediaSource to a MediaElement, it hasn't yet reached open
state (and sourcebuffers cannot be created for the MediaSource). Once it's
attached, (setWebMediaSourceAndOpen()), then AddId() can create SourceBuffers.

So, at creation time, SourceBuffers should know they are part of an 'open'
MediaSource that is attached to a mediaElement.
So why not create these in ctor? (The SourceBuffer ctor is only available via
::create, which is only available via MediaSource.AddId()).

Later, if MediaSource is detached from the element, the spec is a quite a bit
less clear, unfortunately, around what happens to the SB's tracks (and
associated mediaElement tracks). I think the idea would be to do something
similar to the "removeSourceBuffer()" steps as part of detaching from the
element. WDYT? This also needs some testing.

[servolk, 2016/03/31 00:03:40]

Yes, I've changed this already in the previous CL. The track lists are now going
to be created in SB constructor. As for MediaSource being detached from the
element, I think it's covered in MSE spec at
https://w3c.github.io/media-source/#mediasource-detach. Steps 3 and 5 say that
all sourcebuffers should be removed, so yes we'll need to run removeSourceBuffer
and that will take care of media tracks. But you are right in that there seems
to be no test coverage for this atm. I'll try to fix it in a separate CL.

[wolenetz, 2016/03/31 18:57:59]

Acknowledged.

+}
+
+VideoTrackList& SourceBuffer::videoTracks()
+{
+    ASSERT(RuntimeEnabledFeatures::audioVideoTracksEnabled());
+    return *m_videoTracks;
+}
+
 double SourceBuffer::appendWindowStart() const
 {
     return m_appendWindowStart;
@@ -506,11 +519,18 @@ void SourceBuffer::initializationSegmentReceived(const WebVector<WebMediaPlayer:
         return;
     }
 
+    if (!m_audioTracks)
+        m_audioTracks = AudioTrackList::create(*m_source->mediaElement());
+    if (!m_videoTracks)
+        m_videoTracks = VideoTrackList::create(*m_source->mediaElement());
+
     for (const auto& trackId : m_audioTrackIds) {
         m_source->mediaElement()->audioTracks().remove(trackId);
+        audioTracks().remove(trackId);
     }
     for (const auto& trackId : m_videoTrackIds) {
         m_source->mediaElement()->videoTracks().remove(trackId);
+        videoTracks().remove(trackId);
     }
     m_audioTrackIds.clear();
     m_videoTrackIds.clear();
@@ -521,11 +541,13 @@ void SourceBuffer::initializationSegmentReceived(const WebVector<WebMediaPlayer:
                 if (track->type() == WebMediaPlayer::AudioTrack) {
                     AudioTrack* audioTrack = static_cast<AudioTrack*>(track.get());
                     WTF_LOG(Media, "Tracks (sb=%p): adding audioTrack %p trackId=%d id=%s label=%s lang=%s", this, audioTrack, audioTrack->trackId(), audioTrack->id().utf8().data(), audioTrack->label().utf8().data(), audioTrack->language().utf8().data());
+                    audioTracks().add(audioTrack);
                     m_source->mediaElement()->audioTracks().add(audioTrack);
                     m_audioTrackIds.append(trackId);
                 } else if (track->type() == WebMediaPlayer::VideoTrack) {
                     VideoTrack* videoTrack = static_cast<VideoTrack*>(track.get());
                     WTF_LOG(Media, "Tracks (sb=%p): adding videoTrack %p trackId=%d id=%s label=%s lang=%s", this, videoTrack, videoTrack->trackId(), videoTrack->id().utf8().data(), videoTrack->label().utf8().data(), videoTrack->language().utf8().data());
+                    videoTracks().add(videoTrack);
                     m_source->mediaElement()->videoTracks().add(videoTrack);
                     m_videoTrackIds.append(trackId);
                 }
@@ -539,17 +561,25 @@ void SourceBuffer::initializationSegmentReceived(const WebVector<WebMediaPlayer:
 WebMediaPlayer::TrackId SourceBuffer::createMediaTrack(WebMediaPlayer::TrackType type, WebString id, WebString kind, WebString label, WebString language)
 {
     TrackBase* result = nullptr;
+    const char* typeStr = "";
     switch (type) {
     case WebMediaPlayer::AudioTrack:
         result = AudioTrack::create(id, kind, label, language, false);
+        new SourceBufferTrackBaseSupplement(*result, this);
+        typeStr = "audio";
         break;
     case WebMediaPlayer::TextTrack:
         result = TextTrack::create(kind, label, language);
+        typeStr = "text";
         break;
     case WebMediaPlayer::VideoTrack:
         result = VideoTrack::create(id, kind, label, language, false);
+        new SourceBufferTrackBaseSupplement(*result, this);
+        typeStr = "video";
         break;
     }
+    ASSERT_UNUSED(typeStr, typeStr);
+    WTF_LOG(Media, "SourceBuffer(%p)::createMediaTrack: %s track %p trackId=%d id=%s label=%s lang=%s", this, typeStr, result, result->trackId(), result->id().utf8().data(), result->label().utf8().data(), result->language().utf8().data());
 
     ASSERT(result);
     m_pendingTracks.append(result);
@@ -937,6 +967,8 @@ DEFINE_TRACE(SourceBuffer)
     visitor->trace(m_pendingTracks);
     visitor->trace(m_audioTrackIds);
     visitor->trace(m_videoTrackIds);
+    visitor->trace(m_audioTracks);
+    visitor->trace(m_videoTracks);
     RefCountedGarbageCollectedEventTargetWithInlineData<SourceBuffer>::trace(visitor);
     ActiveDOMObject::trace(visitor);
 }