Allow primary dirs under cross-user root as well.

Some app clone implementations have clone apps store their data under a
subdirectory under the owner user's root, eg
/storage/emulated/0/AppClone/ . For those cases, we should still allow
the regular scoped storage exemptions of eg storing downloads in the
correct folder. So instead of just allowing
/storage/emulated/0/Downloads, allow folders like
/storage/emulated/0/AppClone/Downloads as well.

Caveats: this is currently enabled with a sysprop, and only if cross
user access is enabled. It also only supports a single top-level dir (eg
AppClone/, not AppClone/Root/).

Bug: 174685395
Test: N/A
Change-Id: I9c57cf6d400f672cfc560437cac3e68cd9a0f9e6
1 file changed