GitLab

In the old SystemTray, user button was not focusable when there was only
one user account on the device.

TEST=manual
BUG=863337

Change-Id: I8373b144371fce060c454ae07e7456f1fe914a4f
Reviewed-on: https://chromium-review.googlesource.com/1164869Reviewed-by: Yoshiki Iguchi <yoshiki@chromium.org>
Commit-Queue: Tetsui Ohkubo <tetsui@chromium.org>
Cr-Commit-Position: refs/heads/master@{#581429}