Null-check result string.

        final String rs = ei.mResultString;

        // An error can occur here only under extremely unlikely conditions.

        // Check anyway, and just refuse.

        if (ei.mResultString == ERRONEOUS_RESULT) {

        // rs *should* never be null, but it happens. Check as a workaround to protect against

        // crashes until we find the root cause (b/34801142)

        if (rs == ERRONEOUS_RESULT || rs == null) {

            return null;

        }

        final int dotIndex = rs.indexOf('.');