Proposal to integrate pointer lock with the permissions API

[takumif]

We (on the Chrome team) are working on putting pointer lock and keyboard lock behind permission prompts (Chrome Platform Status).

One piece of feedback that we got from a first-party developer that uses keyboard lock is that they'd like to have the permission state exposed via the permissions API so that they can update their UI according to the permission state. We believe the same use case applies to pointer lock.

The pointer lock API spec mentions:

User agents may prompt for confirmation before locking, this preference may be saved as a content setting.

but does not mention the permissions API. We propose to add a section about integrating with the permissions API, similarly to how other APIs such as window management do.