Merge "Revert "No direct Uri grants from system.""

        // Third...  does the caller itself have permission to access

        // this uri?

        final int callingAppId = UserHandle.getAppId(callingUid);

        if ((callingAppId == Process.SYSTEM_UID) || (callingAppId == Process.ROOT_UID)) {

            Slog.w(TAG, "For security reasons, the system cannot issue a Uri permission"

                    + " grant to " + grantUri + "; use startActivityAsCaller() instead");

            return -1;

        } else {

        if (UserHandle.getAppId(callingUid) != Process.SYSTEM_UID) {

            if (!checkHoldingPermissionsLocked(pm, pi, grantUri, callingUid, modeFlags)) {

                // Require they hold a strong enough Uri permission

                if (!checkUriPermissionLocked(grantUri, callingUid, modeFlags)) {