Set a11y name from popover when title is not existing

If an element has a popover where it's content is plain, then it can be used to compute the name as done with titles. This CL implements this feature. Check the issue for more details.

Plain content is elements that are a text field or an image, and all the children are also plain content by this definition.

Fixed: 1329534
Change-Id: I49e2000ffbcd9cdc59cc6a8ecf4b92609cef64da
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4355134


Commit-Queue: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: David Tseng <dtseng@chromium.org>
Reviewed-by: Xiyuan Xia <xiyuan@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Reviewed-by: Arthur Sonzogni <arthursonzogni@chromium.org>
Reviewed-by: Aaron Leventhal <aleventhal@chromium.org>
Reviewed-by: Mason Freed <masonf@chromium.org>
Auto-Submit: Ahmed Elwasefi (Ahmad45123) <a.m.elwasefi@gmail.com>
Cr-Commit-Position: refs/heads/main@{#1123193}