Implement the QuicTransport server session subclass.

This currently does not handle incoming streams, as those require special logic to prevent access to application data before the indication is received.

gfe-relnote: n/a (not used in production)
PiperOrigin-RevId: 274228824
Change-Id: Ie1cd37ecfb739d1242a3cdc40186bca00f8373fd
diff --git a/quic/core/quic_error_codes.h b/quic/core/quic_error_codes.h
index 298029f..ce5c721 100644
--- a/quic/core/quic_error_codes.h
+++ b/quic/core/quic_error_codes.h
@@ -339,8 +339,11 @@
   // There are too many buffered control frames in control frame manager.
   QUIC_TOO_MANY_BUFFERED_CONTROL_FRAMES = 124,
 
+  // QuicTransport received invalid client indication.
+  QUIC_TRANSPORT_INVALID_CLIENT_INDICATION = 125,
+
   // No error. Used as bound while iterating.
-  QUIC_LAST_ERROR = 125,
+  QUIC_LAST_ERROR = 126,
 };
 // QuicErrorCodes is encoded as four octets on-the-wire when doing Google QUIC,
 // or a varint62 when doing IETF QUIC. Ensure that its value does not exceed