Chromium: Don't cache the accessible parent
Chromium: Don't cache the accessible parent

Chromium doesn't always emit parent-change events. While we don't listen
for those ourselves, those events tell AT-SPI2 to update the cached parent.
If we cache the parent, then we can wind up getting stuck. Example page is
the Github issue page when the issue search field gets focus.

We need to get this fixed in Chromium, but in the meantime this should
make common pages like github work better.

GNOME/orca,GNOME/orca,GNOME/orca,GNOME/orca