1923524 - Use AXAnnouncementRequested for all chrome-based live regions

Status: NEW

(Core :: Disability Access APIs, defect)

Description

[Morgan Reschenberg [:morgan]]

On macOS, VoiceOver inconsistently announces live regions when they are in a chrome context. We get around this via a11yUtils.announce, but since this issue is platform specific (and since other chrome-having apps like Thunderbird can't access a11yUtils) we should really just re-route the live region notifications internally to use AXAnnouncementRequested like we do for a11yUtils.announce.

It is important to note that the announcement structure of AXAnnouncementRequested differs from AXLiveRegionChanged -- we must supply both a priority and a title for the former, where VO deduces this information for the latter.

I'm not sure how to supply a title for a live region mutation, given we don't have an event that tells us the node that has changed (we have an event on the node that the change occurred inside of). Priority should be straightforward, we can use the polite/assertive values to deduce one.

Comment 1

[Morgan Reschenberg [:morgan]]

Attachment: Bug 1923524 - Fire AXAnnouncementRequested for all live region changes in a chrome context r?eeejay