Change window_update frame's byte_offset to max_data to incorporate IETF spec. https://tools.ietf.org/html/draft-ietf-quic-transport-24#section-19.10 gfe-relnote: name change only. Not protected. PiperOrigin-RevId: 281838511 Change-Id: I716cfd6856d8c9dd9981040f68bc0567feaedaee