Add a merely pass-through QuicMultipathSentPacketManager. Protected behind blocked flag FLAGS_quic_…

net/quic/quic_protocol.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_QUIC_PROTOCOL_H_
 #define NET_QUIC_QUIC_PROTOCOL_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 664 matching lines @@
   // previous handshake message.
   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,
 
+  // Multipath errors.
   // Multipath is not enabled, but a packet with multipath flag on is received.
   QUIC_BAD_MULTIPATH_FLAG = 79,
+  // A path is supposed to exist but does not.
+  QUIC_MULTIPATH_PATH_DOES_NOT_EXIST = 91,
+  // A path is supposed to be active but is not.
+  QUIC_MULTIPATH_PATH_NOT_ACTIVE = 92,
 
   // IP address changed causing connection close.
   QUIC_IP_ADDRESS_CHANGED = 80,
 
   // Connection migration errors.
   // Network changed, but connection had no migratable streams.
   QUIC_CONNECTION_MIGRATION_NO_MIGRATABLE_STREAMS = 81,
   // Connection changed networks too many times.
   QUIC_CONNECTION_MIGRATION_TOO_MANY_CHANGES = 82,
   // Connection migration was attempted, but there was no new network to
   // migrate to.
   QUIC_CONNECTION_MIGRATION_NO_NEW_NETWORK = 83,
   // Network changed, but connection had one or more non-migratable streams.
   QUIC_CONNECTION_MIGRATION_NON_MIGRATABLE_STREAM = 84,
 
   // No error. Used as bound while iterating.
-  QUIC_LAST_ERROR = 91,
+  QUIC_LAST_ERROR = 93,
 };
 
 typedef char DiversificationNonce[32];
 
 struct NET_EXPORT_PRIVATE QuicPacketPublicHeader {
   QuicPacketPublicHeader();
   explicit QuicPacketPublicHeader(const QuicPacketPublicHeader& other);
   ~QuicPacketPublicHeader();
 
   // Universal header. All QuicPacket headers will have a connection_id and
@@ skipping 785 matching lines @@
       : iov(iov), iov_count(iov_count), total_length(total_length) {}
 
   const struct iovec* iov;
   const int iov_count;
   const size_t total_length;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_PROTOCOL_H_