[DL] Add a cloneNode web_test for display locking.

This test ensures that cloned copies are not automatically locked.

R=chrishtr@chromium.org, rakina@chromium.org

Bug: 882663
Change-Id: Ib50b1e776b5fe5569403ae3c08604609e74880ed
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1509452
Reviewed-by: Rakina Zata Amni <rakina@chromium.org>
Reviewed-by: Chris Harrelson <chrishtr@chromium.org>
Commit-Queue: vmpstr <vmpstr@chromium.org>
Cr-Commit-Position: refs/heads/master@{#639520}
1 file changed