Is this Chrome only or something the other browsers are working on, too? A quick web search does not seem to produce any relevant hits.
Seems Chrome-only for now. But the spec (Working draft) has an editor from Mozilla as well, so maybe someday... https://w3c.github.io/mediacapture-extensions/#the-usermedia...
Apple and Firefox are running tests on the previous parts of this that recently came out (geolocation), so they will be doing the same with this one.
At the very least, Firefox's position on the similar <geolocation> element is positive.[0] I would assume their position for other permissions elements would be the same.
[0]: https://github.com/mozilla/standards-positions/issues/1288