Send an ack when it 20 packets have been received since the last ack was

net/quic/quic_connection.h

Index: net/quic/quic_connection.h
diff --git a/net/quic/quic_connection.h b/net/quic/quic_connection.h
index 9251c20ef1ce0285afe999fca75104a22a5d9ca1..c734387ba696eaf34114255fc1312a60e0c25599 100644
--- a/net/quic/quic_connection.h
+++ b/net/quic/quic_connection.h
@@ -723,6 +723,8 @@ class NET_EXPORT_PRIVATE QuicConnection
 
   // Indicates whether an ack should be sent the next time we try to write.
   bool ack_queued_;
+  // Indicates how many consecutive packets have arrived without sending an ack.
+  uint32 num_packets_received_since_last_ack_sent_;
   // Indicates how many consecutive times an ack has arrived which indicates
   // the peer needs to stop waiting for some packets.
   int stop_waiting_count_;