Remove multipath_enabled from quic_config and quic_connection. No functional change expected.

net/quic/core/quic_config.h

Index: net/quic/core/quic_config.h
diff --git a/net/quic/core/quic_config.h b/net/quic/core/quic_config.h
index 286ba1c2af66e1904cf26c7618d1e7c2e28b54a3..1b0cf9c62186b51d1d44862ee6bf0851f001f6fd 100644
--- a/net/quic/core/quic_config.h
+++ b/net/quic/core/quic_config.h
@@ -351,10 +351,6 @@ class QUIC_EXPORT_PRIVATE QuicConfig {
 
   uint32_t ReceivedSocketReceiveBuffer() const;
 
-  void SetMultipathEnabled(bool multipath_enabled);
-
-  bool MultipathEnabled() const;
-
   void SetDisableConnectionMigration();
 
   bool DisableConnectionMigration() const;
@@ -428,9 +424,6 @@ class QUIC_EXPORT_PRIVATE QuicConfig {
   // TODO(ianswett): Deprecate once QUIC_VERSION_34 is deprecated.
   QuicFixedUint32 socket_receive_buffer_;
 
-  // Whether to support multipath for this connection.
-  QuicNegotiableUint32 multipath_enabled_;
-
   // Whether tell peer not to attempt connection migration.
   QuicFixedUint32 connection_migration_disabled_;