Move source of truth for GetPreferred/ChosenDataTypes to SyncUserSettings

Bug: 884159
Change-Id: I1f9e743cfc364aacafe62b13c2ffa2582c49d418
Reviewed-on: https://chromium-review.googlesource.com/c/1382483
Reviewed-by: calamity <calamity@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#622400}
7 files changed