Intent to prototype: ariaNotify

[James Teh]

Summary: An imperative API for accessibility notifications as a more ergonomic and reliable alternative to ARIA live regions.

Bug: https://bugzilla.mozilla.org/show_bug.cgi?id=2005588

Specification: https://github.com/w3c/aria/pull/2577

Platform coverage: desktop, Android

Preference: accessibility.ariaNotify.enabled

Link to standards-positions discussion: https://github.com/mozilla/standards-positions/issues/1049

Other browsers:

  Blink: shipped since version 141

  WebKit: support; https://github.com/WebKit/standards-positions/issues/370

web-platform-tests: https://github.com/web-platform-tests/wpt/tree/master/core-aam/arianotify; manual because it's not currently possible to test accessibility events in automated WPT

How stable is the spec: pull request isn't yet merged, but I don't anticipate any substantive changes before it is.

Jamie