[webrtc-pc] Should we surface a=msid changes to JS, even though they're not compliant with draft-jsep? (#2115)

docfaraday has just created a new issue for https://github.com/w3c/webrtc-pc:

== Should we surface a=msid changes to JS, even though they're not compliant with draft-jsep? ==
draft-jsep says that a=msid attributes, once set, are invariant until the corresponding transceiver is stopped. webrtc-pc does not seem to say anything about this invariance, which means that if a=msid _does_ change in a remote description, we surface that change to content.

Was this invariance imposed because we did not want to surface such changes to content? Or was there some other reason?

Please view or discuss this issue at https://github.com/w3c/webrtc-pc/issues/2115 using your GitHub account