GitLab

Allow setting the ax child tree id property on the
full screen shell surface.

Bug: None
Test: Manual w/display assistant build
Change-Id: I465e45dc37038ea3c36131fb04a8d57c7b94f3d0
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1720867Reviewed-by: Mitsuru Oshima <oshima@chromium.org>
Commit-Queue: Randy Rossi <rmrossi@chromium.org>
Cr-Commit-Position: refs/heads/master@{#682713}