Tell the QUIC AckNotifierManager about packets on serialization, rather

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index 6f97b5163bbe8ae2e3bb91620ef45198344becac..22fd859468b352600318eff33c3ffb7d5693d7cb 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -1593,6 +1593,10 @@ void QuicConnection::OnSerializedPacket(
   if (serialized_packet.retransmittable_frames) {
     serialized_packet.retransmittable_frames->
         set_encryption_level(encryption_level_);
+
+    if (FLAGS_quic_ack_notifier_informed_on_serialized) {
+      sent_packet_manager_.OnSerializedPacket(serialized_packet);
+    }
   }
   SendOrQueuePacket(QueuedPacket(serialized_packet, encryption_level_));
 }