Fix Supervision Onboarding browser tests.

The tests were flaky due to a race condition with the HTTPSForwarder
initialization. By performing a login before the SetUpOnMainThread exits
we can eliminate that problem.

Tested on my machine by doing about 80 runs for all tests.

Bug: 965369
Change-Id: If86b03f82ad0482d1098aad26613466118b7fcf8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1627453
Commit-Queue: Lucas TenĂ³rio <ltenorio@chromium.org>
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/heads/master@{#662845}
1 file changed