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

net/quic/core/quic_connection.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.
 //
 // The entity that handles framing writes for a Quic client or server.
 // Each QuicSession will have a connection associated with it.
 //
 // On the server side, the Dispatcher handles the raw reads, and hands off
 // packets via ProcessUdpPacket for framing and processing.
 //
@@ skipping 1061 matching lines @@
 
   // The size of the largest packet received from peer.
   QuicByteCount largest_received_packet_size_;
 
   // Whether a GoAway has been sent.
   bool goaway_sent_;
 
   // Whether a GoAway has been received.
   bool goaway_received_;
 
-  // If true, multipath is enabled for this connection.
-  bool multipath_enabled_;
-
   // Indicates whether a write error is encountered currently. This is used to
   // avoid infinite write errors.
   bool write_error_occured_;
 
   // Indicates not to send or process stop waiting frames.
   bool no_stop_waiting_frames_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicConnection);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_QUIC_CONNECTION_H_