[Sync] Move SyncUserSettingsImpl to components/sync/driver

Bug: 896303,884159,906611
Change-Id: I359b1893cc6f8b32ab2039ee02823dee3850f3f2
Reviewed-on: https://chromium-review.googlesource.com/c/1451889
Commit-Queue: Maksim Moskvitin <mmoskvitin@google.com>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#628761}
10 files changed