TrackList and Tracks shouldn't be exposed in a DedicatedWorker.

[jyavenard]

A SourceBuffer exposes all its tracks related objects in a Worker
https://w3c.github.io/media-source/#webidl-544711679
readonly attribute AudioTrackList audioTracks;
readonly attribute VideoTrackList videoTracks;
readonly attribute TextTrackList textTracks;

Track objects are currently only exposed at the Window level
An issue was open to expose them at the Worker level in #280

As noted in #280
There are unfortunately much more DOM objects that need updating, in particular TextTrackCueList / TextTrackCue ; in TextTrack the method addCue and removeCue which have references on how they are to be rendered on the MediaElement (https://w3c.github.io/webvtt/#rules-for-updating-the-display-of-webvtt-text-tracks) with their respective CSS block boxes etc..
while those examples are in relation to WebVTT, there's nothing preventing the use of WebVTT cues in inbandTextTrack

None of which is applicable with DedicatedWorker

Considering there are no User Agent other than webkit implementing Tracks objects in the SourceBuffer when in a DedicatedWorker

We think that those objects shouldn't be exposed in a Worker as they wouldn't be usable anyway.

[padenot]

We think that those objects shouldn't be exposed in a Worker as they wouldn't be usable anyway.

Agreed.