Don't close ancestor popovers when fullscreening

[josepharhar]

Without this patch, the fullscreening an element inside an open popover will make the fullscreen element display:none.

Issue: https://github.com/whatwg/html/issues/9998 Corresponding HTML PR: https://github.com/whatwg/html/pull/10116

• [ ] At least two implementers are interested (and none opposed):
  • Chrome
  • …
• [x] Tests are written and can be reviewed and commented upon at:
  • https://github.com/web-platform-tests/wpt/pull/44146
• [ ] Implementation bugs are filed:
  • Chromium: https://bugs.chromium.org/p/chromium/issues/detail?id=1520938
  • Gecko: …
  • WebKit: …
• [ ] MDN issue is filed: …
• [x] The top of this comment includes a clear commit message to use.

(See WHATWG Working Mode: Changes for more details.)

---

Preview | Diff

[josepharhar]

This probably won't build until definitions are exported in https://github.com/whatwg/html/pull/10116

[josepharhar]

@keithamus does your firefox patch also do fullscreen or just dialogs? https://phabricator.services.mozilla.com/D200686

[mfreed7]

Side-note, the equivalent changes landed yesterday in HTML for <dialog>.

[keithamus]

@keithamus does your firefox patch also do fullscreen or just dialogs? https://phabricator.services.mozilla.com/D200686

Just dialogs. Want me to raise one for fullscreen too?

[josepharhar]

@keithamus yes that would be great! then i can link to the bug in the OP

[keithamus]

https://bugzilla.mozilla.org/show_bug.cgi?id=1888088 & https://phabricator.services.mozilla.com/D205802

[smaug----]

(uh, popovers are causing troubles everywhere)

[josepharhar]

@foolip @domenic could I get a review of this? The corresponding HTML PR has been merged and I filled out the OP