Add support for calculating the accessible label and the accessible role of elements

[AutomatedTester]

…ole of elements

Fixes #1439

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[AutomatedTester]

This is to start getting feedback from accessibility teams. If they are happy I will add wpt

[andreastt]

I don’t know ARIA so I’m relying on @cookiecrook’s judgement that these are the right things to expose.

I have a couple of questions and a few concerns:

• Are these ARIA concepts that is implementable in all browsers?
• Is there vendor commitment to implement these WebDriver endpoints?
• Should this go in th WebDriver core spec, or should they be WebDriver extensions within ARIA?
• There are no tests.

There is precedence for non-core web standards to extend WebDriver to expose automation endpoints. This is what the Permissions API does and would likely serve as a good example to follow here.

Beyond this, there are a few very minor editorial issues to address.

[cookiecrook]

I don’t know ARIA so I’m relying on @cookiecrook’s judgement that these are the right things to expose.

I have a couple of questions and a few concerns:

• Are these ARIA concepts that is implementable in all browsers?

Neither of these is specific to ARIA so it would not make sense to tie them to that spec.

If you wanted to group them, you could possibly call them "accessibility"-specific but the lines between accessibility and mainstream are pretty blurry already. Accessibility as a grouping may make sense because other accessibility concepts (some ARIA-related) may be needed later.

• Is there vendor commitment to implement these WebDriver endpoints?

Yes for these two. Right now it's the lowest common denominator that every vendor agrees would be useful here. Each major vendor (Blink, WebKit, Gecko) has these exposed in Developer Tools contexts already, so I expect implementation will be trivial.

• Should this go in th WebDriver core spec, or should they be WebDriver extensions within ARIA?

Not ARIA specific, so it'd be inappropriate to host it there.

Also, this came up at the TPAC F2F, and I confirmed they are not otherwise available in the JavaScript context. If I understood @AutomatedTester correctly (or was it another WebDriver WG member?), that means these would have be in the core WebDriver spec.

Every major vendor has these concepts central in each implementation, but there is no way to get at this from an over-the-counter JavaScript context currently... Exposing them in WebDriver would allow us to test implementations against each other.

[andreastt]

Very good, thanks! That dispels most of my concerns.

What is missing then are the editorial fixups and tests for this to move forward.

Concerns are addressed per comment

[jgraham]

Tests are web-platform-tests/wpt#23793