Add WPT for popover exception check
The "if (exception_state)" check in ShowPopoverInternal when the
popover's type is changed is not covered in the spec and didn't have a
corresponding WPT, so this patch adds it.
whatwg/html#10451
whatwg/html#10473
Change-Id: I53d6bfa67936c24bc44e1650e0eb6dce32a6bd2e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5696326
Reviewed-by: Di Zhang dizhangg@chromium.org
Commit-Queue: Joey Arhar jarhar@chromium.org
Cr-Commit-Position: refs/heads/main@{#1326473}