Fix the custom passphrase tests which were failing on official builds.

The tests would time out on official builds when setting up sync with
only the decryption passphrase. What happened was that during
SetupSyncImpl, the SyncSetupChecker in AwaitSyncSetupCompletion() did
not finish. This is actually not surpising, as setting up decryption
did not call FinishSyncSetup() and thus the first setup was not marked
as completed. The only reason why this works on non-google branded builds
is that those have "sync-the-transport without sync-the-feature enabled"
which allows getting the transport in an active state (which is still not
the expected state though). This CL fixes that and makes sure we wait
for the sync feature to be ready.

This CL restructures the code so that the decryption passphrase also
gets set within SetupSyncImpl and removes the ability to skip passphrase
verification checks. In fact, many of the are not needed any more now
that we know we should not end up in the missing passphrase state.

BUG=902297

Change-Id: I8badb9ec5cc04fe723ebe1731eae7dcbfc5ceb54
Reviewed-on: https://chromium-review.googlesource.com/c/1415262
Commit-Queue: Tim Schumann <tschumann@chromium.org>
Reviewed-by: Robert Kaplow <rkaplow@chromium.org>
Reviewed-by: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#624591}
10 files changed