SyncService::GetActiveDataTypes: return "none" if there is a persistent auth error

This seems like the safer (and more accurate) interpretation of "active".
In particular, this will affect the "Sync paused" state, for which we previously
claimed that all data types were active.

Bug: 913984
Change-Id: Iea5b0fd113cfc2d12b7173205302abb8fa862cc7
Reviewed-on: https://chromium-review.googlesource.com/c/1402877
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Mikel Astiz <mastiz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#623190}
4 files changed