Remove Supervision Onboarding features.

Bug: 977566
Change-Id: I697e026c9b2574b7d4e5b8491709b98da5919525
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1673018
Commit-Queue: Lucas TenĂ³rio <ltenorio@chromium.org>
Reviewed-by: Michael Giuffrida <michaelpg@chromium.org>
Cr-Commit-Position: refs/heads/master@{#672054}
4 files changed