Inspired by conversation in #199, we have noted that the heuristics being implemented by Chrome and Safari around auto-playing media with sound are creating a situation where sites may need to "earn" the ability to auto-play.

This sounds very much like the sort of asynchronous decision made by the Progressive Web App install prompt system in various browsers and interventions being considered for permissions which are being pervasively requested at load time (but without user interaction).

In these cases, it seems as though browsers will always intervene on behalf of users. Developers will struggle to understand the situation until the reflection APIs get better. One possible alternative would be to model auto-playing media within the Permissions API which already includes a notification mechanism to let developers know when browsers change the status of a permission.

It may be necessary to extend the PermissionState enum to handle this situation.

/cc @owencm @jyasskin