fix: Allow VoiceOver to navigate "back into" web contents

[felixrieseberg]

Description of Change

After some consultation with our friends at Apple, I've figured out why exactly VoiceOver has such trouble getting "back into" web contents when it was first navigated out. As it turns out, by default, there is no RenderWidgetHostViewCocoa in the AXChildren array, so our custom filter ensuring that it's included doesn't do anything. Instead, the web contents are part of a class named BrowserAccessibilityCocoa.

[Note: I've previously tried to fix this by manually adding the contentView, which worked in some cases, but not all]

Checklist

• PR description included and stakeholders cc'd
• npm test passes
• tests are changed or added
• relevant documentation is changed or added
• PR title follows semantic commit guidelines
• PR release notes describe the change in a way relevant to app developers, and are capitalized, punctuated, and past tense.
• This is NOT A BREAKING CHANGE. Breaking changes may not be merged to master until 11-x-y is branched.

Release Notes

Notes: Fixes an issue where VoiceOver was unable to navigate from the top-level window back into the web contents

[codebytere]

@felixrieseberg do you by chance have a reference for this or are we just sort of trusting manual testing and what Apple says? i'm ok with this but have mild concern it might change again in the future and would love to know where we can look for this kind of information 🤔

[felixrieseberg]

@codebytere God, I wish I had a good answer for you - that would have made this a lot easier. This PR is the result of some manual testing by Slack's a11y people and an email thread with Apple where some helpful AX experts told me to please fix the parent-child relationship.

Actually, as I'm writing this out, we'd probably be better off removing the thing we don't want in the array instead of manually keeping things. Let me amend the PR, because that'd solve our problem here - if things change again in the future, we wouldn't have to change anything in this code.

[release-clerk]

Release Notes Persisted

Fixes an issue where VoiceOver was unable to navigate from the top-level window back into the web contents

[trop]

I have automatically backported this PR to "10-x-y", please check out #24698

[trop]

I have automatically backported this PR to "9-x-y", please check out #24699