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
diff --git a/quic/core/quic_session.cc b/quic/core/quic_session.cc
index 1c85430..cba27f0 100644
--- a/quic/core/quic_session.cc
+++ b/quic/core/quic_session.cc
@@ -454,9 +454,9 @@
     // individual stream.
     QUIC_DVLOG(1) << ENDPOINT
                   << "Received connection level flow control window "
-                     "update with byte offset: "
-                  << frame.byte_offset;
-    flow_controller_.UpdateSendWindowOffset(frame.byte_offset);
+                     "update with max data: "
+                  << frame.max_data;
+    flow_controller_.UpdateSendWindowOffset(frame.max_data);
     return;
   }