Remove last encryption-related methods from SyncService

This removes IsUsingSecondaryPassphrase and
IsPassphraseRequiredForDecryption from SyncService.
These are now accessed through SyncUserSettings

Bug: 884159
Change-Id: I3aaa6eb20f3d2f6784fc128d671da05bf6b16041
Reviewed-on: https://chromium-review.googlesource.com/c/1437085
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Reviewed-by: Christian Dullweber <dullweber@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: Sebastien Seguin-Gagnon <sebsg@chromium.org>
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Vasilii Sukhanov <vasilii@chromium.org>
Reviewed-by: calamity <calamity@chromium.org>
Cr-Commit-Position: refs/heads/master@{#627880}
25 files changed