Add a QUIC tag to connection options to allow negotiating 1 connection

net/quic/congestion_control/tcp_cubic_sender.cc

 // 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.
 
 #include "net/quic/congestion_control/tcp_cubic_sender.h"
 
 #include <algorithm>
 
 #include "base/metrics/histogram.h"
 #include "net/quic/congestion_control/rtt_stats.h"
@@ skipping 61 matching lines @@
                                config.ReceivedInitialCongestionWindow());
     }
   }
   if (config.HasReceivedSocketReceiveBuffer()) {
     // Set the initial socket receive buffer size in bytes.
     receive_window_ = config.ReceivedSocketReceiveBuffer();
   }
 }
 
 void TcpCubicSender::SetNumEmulatedConnections(int num_connections) {
-  num_connections_ = num_connections;
-  cubic_.SetNumConnections(num_connections);
+  num_connections_ = max(1, num_connections);
+  cubic_.SetNumConnections(num_connections_);
 }
 
 void TcpCubicSender::OnIncomingQuicCongestionFeedbackFrame(
     const QuicCongestionFeedbackFrame& feedback,
     QuicTime feedback_receive_time) {
   if (feedback.type == kTCP) {
     receive_window_ = feedback.tcp.receive_window;
   }
 }
 
@@ skipping 267 matching lines @@
     return QuicTime::Delta::Zero();
   }
   return QuicTime::Delta::Infinite();
 }
 
 CongestionControlType TcpCubicSender::GetCongestionControlType() const {
   return reno_ ? kReno : kCubic;
 }
 
 }  // namespace net