Fix an NPE when launching an activity that's not found.

        // Collect information about the target of the Intent.

        ActivityInfo aInfo = resolveActivity(intent, resolvedType, startFlags,

                profileFile, profileFd, userId);

        if (mService.isSingleton(aInfo.processName, aInfo.applicationInfo)) {

        if (aInfo != null && mService.isSingleton(aInfo.processName, aInfo.applicationInfo)) {

            userId = 0;

        }

        aInfo = mService.getActivityInfoForUser(aInfo, userId);