Apply final changes to policy_PopupsAllowedForUrls test.

Somehow I failed upload the final changes made to files for
policy_PopupsAllowedForUrls and cros/enterprise_policy_base.py, when
I checked in CL 319635. This CL applies those final changes.

BUG=chromium:572947
TEST=Run test_that <IP> policy_PopupsAllowedForUrls

Change-Id: I12c996640f37923bee1e729fcd8094855297b3ef
Reviewed-on: https://chromium-review.googlesource.com/320250
Commit-Ready: Scott Cunningham <scunningham@chromium.org>
Tested-by: Scott Cunningham <scunningham@chromium.org>
Reviewed-by: Scott Cunningham <scunningham@chromium.org>
3 files changed