Chrome OS: Integrate PIN setup into Discover UI

TBR=alemate@chromium.org

(cherry picked from commit f479db8f992be027ddc9b715919df65ad4e40bb6)

Bug: 852553
Change-Id: I460a420b1dd0024eaebb114aac2368a7bb3f28ae
Reviewed-on: https://chromium-review.googlesource.com/c/1249496
Reviewed-by: Devlin <rdevlin.cronin@chromium.org>
Reviewed-by: Jacob Dufault <jdufault@chromium.org>
Commit-Queue: Alexander Alekseev <alemate@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#599130}
Reviewed-on: https://chromium-review.googlesource.com/c/1293180
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Cr-Commit-Position: refs/branch-heads/3578@{#197}
Cr-Branched-From: 4226ddf99103e493d7afb23a4c7902ee496108b6-refs/heads/master@{#599034}
36 files changed