[unified-consent] Take over changes from settings opt-in

Before this CL the user could end up in a weird state
after opting in through the settings flow: When the
user made changes during the settings opt-in, they would
be overridden with (older) changes that were synced down
from the server.
This meant that a user could toggle off a service during
opt-in, hit confirm, and when sync started, the toggle
would be flipped on again.

This CL solves the issue by observing the service prefs
during opt-in and applying changes once the prefs are


Bug: 933647
Change-Id: I2f1fb8d328d6ecf25c11c1c4cf52b8a3e4b26c5e
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1515532
Reviewed-by: Marc Treib <treib@chromium.org>
Commit-Queue: Thomas Tangl <tangltom@chromium.org>
Cr-Commit-Position: refs/heads/master@{#643733}
9 files changed