RTCRtpSender.replaceTrack(null) ends current track

According to the spec, adding and then removing a track from a RTCPeerConnection can be done as follows:

let pc = new RTCPeerConnection();
let sender = pc.addTrack(track, stream);

// Negotiate,...

sender.replaceTrack(null);



This works fine on Chrome and Firefox. On Safari however, the call to replaceTrack() stops the track entirely, setting readyState to "ended" (but interestingly, not calling the onended callback). This makes it impossible to use this method to remove a track that is still used elsewhere. This is problematic, especially since pc.removeTrack(track) is buggy as well: https://bugs.webkit.org/show_bug.cgi?id=174327


This example should demonstrate the issue: https://jsfiddle.net/vt55wx9u/4/.

[Radar WebKit Bug Importer]

<rdar://problem/40758138>

[youenn fablet]

Created attachment 342919 [details]
Patch

[EWS Watchlist]

Comment on attachment 342919 [details]
Patch

Attachment 342919 [details] did not pass mac-wk2-ews (mac-wk2):
Output: http://webkit-queues.webkit.org/results/8229141

New failing tests:
imported/w3c/web-platform-tests/webrtc/RTCRtpSender-replaceTrack.html

[EWS Watchlist]

Created attachment 342920 [details]
Archive of layout-test-results from ews106 for mac-sierra-wk2

The attached test failures were seen while running run-webkit-tests on the mac-wk2-ews.
Bot: ews106  Port: mac-sierra-wk2  Platform: Mac OS X 10.12.6

[EWS Watchlist]

Comment on attachment 342919 [details]
Patch

Attachment 342919 [details] did not pass ios-sim-ews (ios-simulator-wk2):
Output: http://webkit-queues.webkit.org/results/8229193

New failing tests:
imported/w3c/web-platform-tests/webrtc/RTCRtpSender-replaceTrack.html

[EWS Watchlist]

Created attachment 342923 [details]
Archive of layout-test-results from ews124 for ios-simulator-wk2

The attached test failures were seen while running run-webkit-tests on the ios-sim-ews.
Bot: ews124  Port: ios-simulator-wk2  Platform: Mac OS X 10.13.4

[youenn fablet]

Created attachment 342927 [details]
Patch

[Igalia-pontevedra EWS]

Comment on attachment 342927 [details]
Patch

Attachment 342927 [details] did not pass gtk-wk2-ews (gtk-wk2):
Output: http://webkit-queues.webkit.org/results/8238825

New failing tests:
http/tests/resourceLoadStatistics/classify-as-prevalent-based-on-subresource-under-top-frame-origins.html

[Igalia-pontevedra EWS]

Created attachment 342999 [details]
Archive of layout-test-results from ltilve-gtk-wk2-ews for gtk-wk2

The attached test failures were seen while running run-webkit-tests on the gtk-wk2-ews.
Bot: ltilve-gtk-wk2-ews  Port: gtk-wk2  Platform: Linux-4.16.0-0.bpo.1-amd64-x86_64-with-debian-9.4

[youenn fablet]

Comment on attachment 342927 [details]
Patch

gtk error is unrelated

[WebKit Commit Bot]

Comment on attachment 342927 [details]
Patch

Clearing flags on attachment: 342927

Committed r232956: <https://trac.webkit.org/changeset/232956>

[WebKit Commit Bot]

All reviewed patches have been landed.  Closing bug.