This is an archived snapshot of W3C's public bugzilla bug tracker, decommissioned in April 2019. Please see the home page for more details.
While defining in https://github.com/whatwg/html/pull/638 how this is to be implemented I have not found the need for the realm argument. We can "simply" use the current Realm Record. Since I don't think anyone but the HTML standard will use this hook, we should remove it.
Fixed in https://github.com/heycam/webidl/commit/db9912d.