Expose doc-pagefooter, doc-pageheader

This will help online word processors such as Google Docs mark which
elements in the page are repeated content.

There are no specific ATK/IA2 role mappings currently. For now, ATs
on Windows and Linux can use the xml-roles object attribute.

See https://w3c.github.io/dpub-aria/#doc-pagefooter and
https://w3c.github.io/dpub-aria/#doc-pageheader

AX-Relnotes: Add new doc-pageheader and doc-pagefooter roles from DPUB-ARIA 1.1.
Skip-Translation-Screenshots-Check: True
Bug: 1134999
Change-Id: If360a51eb44c1cf2beb1315f1ba48134513dddad
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2448689
Auto-Submit: Aaron Leventhal <aleventhal@chromium.org>
Commit-Queue: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#814112}
GitOrigin-RevId: e22c1f56f28f275a800d48625982f1b133f5657b
1 file changed