GitLab

Reparents signinInteractionCooordinator and cleans up guts interfaces.

Note the new method in SceneControllerGuts that allows MC to cleanup
a SC before shutdown. I think this is fine at least temporarily, but
we need to iron out how this happens in iOS 12 compat in the future.

Bug: none
Change-Id: Ie214b60b830548f1aaec56207298cdf6ba6ddd3e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2007051
Commit-Queue: Stepan Khapugin <stkhapugin@chromium.org>
Reviewed-by: Mark Cogan <marq@chromium.org>
Cr-Commit-Position: refs/heads/master@{#733427}