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

net/quic/quic_unacked_packet_map.h

Index: net/quic/quic_unacked_packet_map.h
diff --git a/net/quic/quic_unacked_packet_map.h b/net/quic/quic_unacked_packet_map.h
index ae72548b9b4c284370d16cbc2dcb0182a3a41e28..0684b4db9f74407792f77edfa997e7514604a16b 100644
--- a/net/quic/quic_unacked_packet_map.h
+++ b/net/quic/quic_unacked_packet_map.h
@@ -77,6 +77,9 @@ class NET_EXPORT_PRIVATE QuicUnackedPacketMap {
                QuicByteCount bytes_sent,
                bool set_in_flight);
 
+  // Restores the in flight status for a packet that was previously sent.
+  void RestoreInFlight(QuicPacketSequenceNumber sequence_number);
+
   // Clears up to |num_to_clear| previous transmissions in order to make room
   // in the ack frame for new acks.
   void ClearPreviousRetransmissions(size_t num_to_clear);