GitLab

This test is very flaky, I believe because it relies on global state,
instead of explicitly setting up the LabInfo used to populate the labs
button. For example, if there were no current labs in SetUpLabs, the
test would fail. So this CL explicitly sets up the LabInfo for the labs
button. It's a bit messy that it requires a change to the production
code, but I didn't see any other way of plumbing that information
through to the model.

Bug: 956719
Change-Id: I8078c211e37fc1eeff50a44043eca760cdc4850a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2618656Reviewed-by: Collin Baker <collinbaker@chromium.org>
Commit-Queue: David Bienvenu <davidbienvenu@chromium.org>
Cr-Commit-Position: refs/heads/master@{#842150}