Explicitly disallow multi-packet CHLOs. Protected by FLAGS_quic_disallow_multi_packet_chlo, default…

net/quic/quic_protocol.h

Index: net/quic/quic_protocol.h
diff --git a/net/quic/quic_protocol.h b/net/quic/quic_protocol.h
index a3801a51ee39764d4da49f17767667499654ee11..3c29220db5037d7f346bdf98b325bd33ed239a7e 100644
--- a/net/quic/quic_protocol.h
+++ b/net/quic/quic_protocol.h
@@ -680,6 +680,8 @@ enum QuicErrorCode {
   QUIC_CRYPTO_MESSAGE_WHILE_VALIDATING_CLIENT_HELLO = 54,
   // A server config update arrived before the handshake is complete.
   QUIC_CRYPTO_UPDATE_BEFORE_HANDSHAKE_COMPLETE = 65,
+  // CHLO cannot fit in one packet.
+  QUIC_CRYPTO_CHLO_TOO_LARGE = 90,
   // This connection involved a version negotiation which appears to have been
   // tampered with.
   QUIC_VERSION_NEGOTIATION_MISMATCH = 55,
@@ -702,7 +704,7 @@ enum QuicErrorCode {
   QUIC_CONNECTION_MIGRATION_NON_MIGRATABLE_STREAM = 84,
 
   // No error. Used as bound while iterating.
-  QUIC_LAST_ERROR = 90,
+  QUIC_LAST_ERROR = 91,
 };
 
 // Must be updated any time a QuicErrorCode is deprecated.