Change the number of emulated connections in QUIC's congestion control

net/quic/quic_sent_packet_manager.cc

Index: net/quic/quic_sent_packet_manager.cc
diff --git a/net/quic/quic_sent_packet_manager.cc b/net/quic/quic_sent_packet_manager.cc
index 553e7e2f69a188ed7a7c2bb78c34323ab5741cf7..a6749ec65ba48e1f97d072ece29e50575c32b437 100644
--- a/net/quic/quic_sent_packet_manager.cc
+++ b/net/quic/quic_sent_packet_manager.cc
@@ -78,6 +78,7 @@ QuicSentPacketManager::QuicSentPacketManager(
                                                      congestion_control_type,
                                                      stats)),
       loss_algorithm_(LossDetectionInterface::Create(loss_type)),
+      n_connection_simulation_(false),
       receive_buffer_bytes_(kDefaultSocketReceiveBuffer),
       least_packet_awaited_by_peer_(1),
       first_rto_transmission_(0),
@@ -125,6 +126,9 @@ void QuicSentPacketManager::SetFromConfig(const QuicConfig& config) {
   if (HasClientSentConnectionOption(config, k1CON)) {
     send_algorithm_->SetNumEmulatedConnections(1);
   }
+  if (HasClientSentConnectionOption(config, kNCON)) {
+    n_connection_simulation_ = true;
+  }
   if (HasClientSentConnectionOption(config, kNTLP)) {
     max_tail_loss_probes_ = 0;
   }
@@ -144,6 +148,14 @@ void QuicSentPacketManager::SetFromConfig(const QuicConfig& config) {
   }
 }
 
+void QuicSentPacketManager::SetNumOpenStreams(size_t num_streams) {
+  if (n_connection_simulation_) {
+    // Ensure the number of connections is between 1 and 5.
+    send_algorithm_->SetNumEmulatedConnections(
+        min<size_t>(5, max<size_t>(1, num_streams)));
+  }
+}
+
 bool QuicSentPacketManager::HasClientSentConnectionOption(
     const QuicConfig& config, QuicTag tag) const {
   if (is_server_) {