This is going to break the consumers of the web activity.  For example:

  https://github.com/mozilla-b2g/gaia/blob/master/apps/email/js/cards/compose.js#L677

This also shows in the unit tests:

  https://travis-ci.org/mozilla-b2g/gaia/jobs/12954613

Its unclear to me if the consumers should be expecting a true mozContact or a normalized "result" object.