Add metrics for OobeConfigRestoreResult

- Adds enum histogram for OobeConfigRestoreResult which represents the
result from attempting to restore a users data during a rollback.
- Emitting to this metric will happen via the ChomeOS Metrics Library

Bug: chromium:881341
Change-Id: Ie44eff2ad99a9a337638c9b473b0034ba838a387
Reviewed-on: https://chromium-review.googlesource.com/c/1407115
Reviewed-by: Steven Holte <holte@chromium.org>
Reviewed-by: Zentaro Kavanagh <zentaro@chromium.org>
Commit-Queue: Bailey Berro <baileyberro@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623526}
2 files changed