Repair the CWND reduction caused by spurious RTO's in QUIC's congestion

net/quic/congestion_control/send_algorithm_interface.h

Index: net/quic/congestion_control/send_algorithm_interface.h
diff --git a/net/quic/congestion_control/send_algorithm_interface.h b/net/quic/congestion_control/send_algorithm_interface.h
index 6b1c75597f73faedce85fb9c8e8fe76fe04a3ae2..01bc2334b6060c3f712b6387725d3934b9a9ad38 100644
--- a/net/quic/congestion_control/send_algorithm_interface.h
+++ b/net/quic/congestion_control/send_algorithm_interface.h
@@ -67,6 +67,9 @@ class NET_EXPORT_PRIVATE SendAlgorithmInterface {
   // nor OnPacketLost will be called for these packets.
   virtual void OnRetransmissionTimeout(bool packets_retransmitted) = 0;
 
+  // Called when the last retransmission timeout was spurious.
+  virtual void RevertRetransmissionTimeout() = 0;
+
   // Calculate the time until we can send the next packet.
   virtual QuicTime::Delta TimeUntilSend(
       QuicTime now,