CrOS FilesApp: Share from DriveFS with crostini container.

Depends on
https://chromium-review.googlesource.com/c/chromiumos/platform2/+/1287389
https://chromium-review.googlesource.com/c/chromiumos/platform2/+/1287390

Bug: 878324
Bug: 890649
Change-Id: I20b57cc7900727fa15ef2de12d247052dd040bff
Reviewed-on: https://chromium-review.googlesource.com/c/1288095
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Ryo Hashimoto <hashimoto@chromium.org>
Reviewed-by: Nicholas Verne <nverne@chromium.org>
Reviewed-by: Sam McNally <sammc@chromium.org>
Reviewed-by: Ilya Sherman <isherman@chromium.org>
Cr-Commit-Position: refs/heads/master@{#602288}
15 files changed