Bug 982663: collect and transmit app usage metrics

In addition to sending this deviceinfo should we also be sending some uuid for this user?  Do we want to be able to connect individual reports together? I would think so, but don't know what our privacy requirements are.  Can I pick a random number the first time we're run and save it in async storage and then send it with each report?  (Actually should clear that number if the service is turned off and pick a new one if turned back on.)