cros: ensure update check to complete at OOBE before allowing login
This CL updates the CrOS login flow to ensure the update check is
complete at OOBE before allowing the first user to log in. Without a
successful check for update, we can't be sure if there is a critical
update. To play safe and avoid missing any critical update during OOBE,
we modify the UI simply goes back to the network selection screen
instead of proceeding to the login screen. For the non-OOBE flow, we
don't want to block the users while failing to check for update, and
thus preseve the existing UI behavior to proceed to the login screen.
BUG=chromium:683424
TEST=Tested the following:
1. Under the OOBE scenario, interrupt the network connectivity when
the UI is checking for update. Verify that the UI goes back to the
network selection screen.
2. Repeat (1) under the non-OOBE scenario. Verify that the UI proceeds
to the login screen.
Review-Url: https://codereview.chromium.org/2676383002
Cr-Commit-Position: refs/heads/master@{#450428}
2 files changed
