Remove many encryption-related methods from [Profile]SyncService

All the methods that are more (static) configuration than (dynamic)
runtime state should be exposed and accessed via SyncUserSettings.

Some methods are more like runtime state, e.g.
IsUsingSecondaryPassphrase (since we know the answer to that only if
the Sync engine is running). Those will remain in SyncService.

For yet some other methods, it's not entirely clear where they should
live, e.g. IsPassphraseRequired. For now, these are left alone.

Some code (mostly tests) is updated to refer to the removed methods
via SyncUserSettings instead of via the SyncService.

Bug: 884159
Change-Id: I42b0aa632945238b4493794da1a8ecf6c6f01a33
Reviewed-on: https://chromium-review.googlesource.com/c/1417472
Reviewed-by: David Roger <droger@chromium.org>
Reviewed-by: Brian White <bcwhite@chromium.org>
Reviewed-by: Istiaque Ahmed <lazyboy@chromium.org>
Reviewed-by: Mohamed Amir Yosef <mamir@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624539}
25 files changed