Register a fake AppInfo with correct OS if it doesn't exist yet. Just use Svc.Crypto instead of trying to dynamically pick the contract id. Name the head files so they load in appinfo -> helper -> http order.
--HG--
rename : services/sync/tests/unit/bookmark_setup.js => services/sync/tests/unit/head_appinfo.js
rename : services/sync/tests/unit/head_first.js => services/sync/tests/unit/head_helpers.js
