Change the defaults QuicConfig::server_initial_congestion_window to be

net/quic/quic_config.cc

 // Copyright (c) 2013 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/quic_config.h"
 
 #include <algorithm>
 
 #include "base/logging.h"
 #include "net/quic/quic_sent_packet_manager.h"
@@ skipping 314 matching lines @@
   congestion_control.push_back(kQBIC);
   congestion_control_.set(congestion_control, kQBIC);
   idle_connection_state_lifetime_seconds_.set(kDefaultTimeoutSecs,
                                               kDefaultInitialTimeoutSecs);
   // kKATO is optional. Return 0 if not negotiated.
   keepalive_timeout_seconds_.set(0, 0);
   max_streams_per_connection_.set(kDefaultMaxStreamsPerConnection,
                                   kDefaultMaxStreamsPerConnection);
   max_time_before_crypto_handshake_ = QuicTime::Delta::FromSeconds(
       kDefaultMaxTimeForCryptoHandshakeSecs);
-  server_initial_congestion_window_.set(kMaxInitialWindow,
+  server_initial_congestion_window_.set(kDefaultInitialWindow,
                                         kDefaultInitialWindow);
 }
 
 void QuicConfig::ToHandshakeMessage(CryptoHandshakeMessage* out) const {
   congestion_control_.ToHandshakeMessage(out);
   idle_connection_state_lifetime_seconds_.ToHandshakeMessage(out);
   keepalive_timeout_seconds_.ToHandshakeMessage(out);
   max_streams_per_connection_.ToHandshakeMessage(out);
   server_initial_congestion_window_.ToHandshakeMessage(out);
   // TODO(ianswett): Don't transmit parameters which are optional and not set.
@@ skipping 58 matching lines @@
         server_hello, error_details);
   }
   if (error == QUIC_NO_ERROR) {
     error = initial_round_trip_time_us_.ProcessServerHello(
         server_hello, error_details);
   }
   return error;
 }
 
 }  // namespace net