Default socket receive buffer to 256K bytes and remove unnecessary

net/quic/congestion_control/tcp_cubic_sender.cc

Index: net/quic/congestion_control/tcp_cubic_sender.cc
diff --git a/net/quic/congestion_control/tcp_cubic_sender.cc b/net/quic/congestion_control/tcp_cubic_sender.cc
index 18401b713b7d11f23925d14f36a161d6e6a4a275..d9677046678881d3f73b16c7c3c6c293ebd8396f 100644
--- a/net/quic/congestion_control/tcp_cubic_sender.cc
+++ b/net/quic/congestion_control/tcp_cubic_sender.cc
@@ -21,7 +21,6 @@ namespace {
 // fast retransmission.  The cwnd after a timeout is still 1.
 const QuicTcpCongestionWindow kMinimumCongestionWindow = 2;
 const QuicByteCount kMaxSegmentSize = kDefaultTCPMSS;
-const QuicByteCount kDefaultReceiveWindow = 64000;
 const int64 kInitialCongestionWindow = 10;
 const int kMaxBurstLength = 3;
 };  // namespace
@@ -38,7 +37,7 @@ TcpCubicSender::TcpCubicSender(
       stats_(stats),
       reno_(reno),
       congestion_window_count_(0),
-      receive_window_(kDefaultReceiveWindow),
+      receive_window_(kDefaultSocketReceiveBuffer),
       prr_out_(0),
       prr_delivered_(0),
       ack_count_since_loss_(0),
@@ -72,6 +71,10 @@ void TcpCubicSender::SetFromConfig(const QuicConfig& config, bool is_server) {
                                config.ReceivedInitialCongestionWindow());
     }
   }
+  if (config.HasReceivedSocketReceiveBuffer()) {
+    // Set the initial socket receive buffer size in bytes.
+    receive_window_ = config.ReceivedSocketReceiveBuffer();
+  }
 }
 
 void TcpCubicSender::OnIncomingQuicCongestionFeedbackFrame(