Core-AAM: Add macOS mapping for aria-errormessage

[joanmarie]

Expose the textual content of the referenced element as the value of
AXHelp.

Fixes github issue #457.

[joanmarie]

@cookiecrook: Please review. Thanks!

[cookiecrook]

We usually don't recommend putting any critical information in AXHelp, since a lot of users will disable VoiceOver speaking help text until a command is issued. I think our options are:

• Append it to the label,
• Trigger an announcement at the time it is shown, or
• Expose it as a new TBD API.

[stes-acc]

>>> … since a lot of users will disable VoiceOver speaking help text until a command is issued.

Is there a specific key or/and gesture to speak AXHelp on request for a given control? - Stefan

[joanmarie]

We usually don't recommend putting any critical information in AXHelp, since a lot of users will disable VoiceOver speaking help text until a command is issued. I think our options are:

• Append it to the label,
• Trigger an announcement at the time it is shown, or
• Expose it as a new TBD API.

Fair enough. Thanks for the review!

Unfortunately, the lack of mapping is one of the things blocking the Core AAM from being able to enter CR. We really, really, really need to know what your platform's mapping is. Patches not only "welcome", but strongly encouraged. 😄

[cookiecrook]

@stes-acc wrote:

Is there a specific key or/and gesture to speak AXHelp on request for a given control?

VO+Cmd+H will speak it on demand. Optionally, but by default, it will be spoken after a user-adjustable-length pause.

[cookiecrook]

Works for me, but I added the last commits, so maybe you should review.

[joanmarie]

Works for me, but I added the last commits, so maybe you should review.

Thanks! What you did works for me. But I couldn't be bothered to figure out how to use github's UI to change authorship as part of a squash and merge, so I just did it the old-fashioned way. 😄. a314c09.

Thanks again!