The following revision refers to this bug:
  https://chromium.googlesource.com/chromiumos/third_party/autotest/+/08d1087b30da30bd2138ae162d9090e7064a6040

commit 08d1087b30da30bd2138ae162d9090e7064a6040
Author: Ruben Zakarian <rzakarian@google.com>
Date: Sat Dec 15 06:40:41 2018

[Autotest] policy_DeviceEphemeralUsersEnabled

This autotest enabled Ephemeral device policy and then verifies it.
It sets it to True, False and None.

BUG= chromium:912974 
TEST=this

Change-Id: I3615199e484e214cac4f4702b17f9ccc9b197675
Reviewed-on: https://chromium-review.googlesource.com/1368268
Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Tested-by: Ruben Zakarian <rzakarian@chromium.org>
Reviewed-by: Katherine Threlkeld <kathrelkeld@chromium.org>

[modify] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/client/cros/enterprise/enterprise_policy_base.py
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/server/site_tests/policy_DeviceServer/control.EphemeralUser_notset
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/server/site_tests/policy_DeviceServer/control.EphemeralUser_false
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/server/site_tests/policy_DeviceServer/control.EphemeralUser_true
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/client/site_tests/policy_DeviceEphemeralUsersEnabled/policy_DeviceEphemeralUsersEnabled.py
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/server/site_tests/policy_DeviceServer/policy_DeviceServer.py
[add] https://crrev.com/08d1087b30da30bd2138ae162d9090e7064a6040/client/site_tests/policy_DeviceEphemeralUsersEnabled/control