GitLab

In the login or lock screen, the settings and lock buttons are inactive so that
we made them invisible to improve UX. In the previous implementation,
these buttons are just disabled instead of invisible.

TEST=TopShortcutsViewTest
BUG=864233

Change-Id: I44b633187b475386732bfa9df5b78e740529d1e7
Reviewed-on: https://chromium-review.googlesource.com/1157666Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Reviewed-by: Tetsui Ohkubo <tetsui@chromium.org>
Commit-Queue: Toshiki Kikuchi <toshikikikuchi@google.com>
Cr-Commit-Position: refs/heads/master@{#580092}