The change is quite simple -- navigator.mozMobileConnection becomes an array of nsIDOMMozMobileConnection obect, i.e. navigator.mozMobileConnections. The length of the array is actually the number of services provided on a device. And the index of the array is used as 'serviceId.'
We don't modify the existed existing interface, like nsIDOMMozMobileConnection, nsIDOMMozMobileConnectionInfo ...etc, to minimize the coding effort of gaia.
interface nsIMozNavigatorMobileConnectionManager: nsISupports