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

net/quic/congestion_control/rtt_stats.h

Index: net/quic/congestion_control/rtt_stats.h
diff --git a/net/quic/congestion_control/rtt_stats.h b/net/quic/congestion_control/rtt_stats.h
index ee8d1809086312aa82d2469f724c5527e5ea1be0..8ceaf21acf7ecc13f78b38bcac099533fc8b753b 100644
--- a/net/quic/congestion_control/rtt_stats.h
+++ b/net/quic/congestion_control/rtt_stats.h
@@ -32,6 +32,10 @@ class NET_EXPORT_PRIVATE RttStats {
                  QuicTime::Delta ack_delay,
                  QuicTime now);
 
+  // Causes the smoothed_rtt to be increased to the latest_rtt and the
+  // mean_variance to be increased to the most recent variance.
+  void ExpireSmoothedMetrics();
+
   // Forces RttStats to sample a new recent min rtt within the next
   // |num_samples| UpdateRtt calls.
   void SampleNewRecentMinRtt(uint32 num_samples);