Updating ui_SystemTray to support guest login.

BUG=chromium:374981
TEST=ran locally against a link device

Change-Id: Ic7e97342eae1c0c1800c72564e4fac6506455b0a
Reviewed-on: https://chromium-review.googlesource.com/225203
Reviewed-by: David Haddock <dhaddock@chromium.org>
Commit-Queue: David Haddock <dhaddock@chromium.org>
Tested-by: David Haddock <dhaddock@chromium.org>
3 files changed