Show network and update screens in demo mode setup flow.

Bug: 857519, 862445
Test: Run DemoSetupTest and wizard_controller_browsertests.
Change-Id: I95a343ad740ac70a1c33db152a3fda1172d10912
Reviewed-on: https://chromium-review.googlesource.com/1141361
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#578019}
5 files changed