FilesApp UI test for not sharing Play files root

UI test for not sharing Play files root.
Original CL is crosreview.com/1616703.
Test in separate CL since it is unlikely to merge well.

Bug: 958840
Change-Id: I6cd5ab216b77890a748f323cc87a223b8fab5ec6
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1619443
Commit-Queue: Joel Hockey <joelhockey@chromium.org>
Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661253}
1 file changed