SyncDisableObserver: Don't use ProfileSyncService::GetSyncTokenStatus

GetSyncTokenStatus is otherwise only used for debug UI, and I'd like to
clearly mark it as such. It's also *almost* identical to other state
exposed from ProfileSyncService.

Behavior difference:
Before: When the access token expires, the ConnectionStatus in the
SyncTokenStatus temporarily changes to CONNECTION_AUTH_ERROR until a
new access token is acquired, and so UKM is temporarily disabled.
After: UKM remains enabled while a new access token is fetched, and
only gets disabled if that fails.

Bug: 839834, 953272
Change-Id: I68a6ada78a654290e2267de10d6430cbf2ae7195
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1065741
Commit-Queue: Marc Treib <treib@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Roger Tawa <rogerta@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Cr-Commit-Position: refs/heads/master@{#653514}
4 files changed