Tell the QUIC AckNotifierManager about packets on serialization, rather

net/quic/quic_sent_packet_manager.cc

Index: net/quic/quic_sent_packet_manager.cc
diff --git a/net/quic/quic_sent_packet_manager.cc b/net/quic/quic_sent_packet_manager.cc
index f2c514b4bcc0b09891ab4413d256e9ac9279be26..ed18f4272207bee9f2d19d512e615e4dbc656f60 100644
--- a/net/quic/quic_sent_packet_manager.cc
+++ b/net/quic/quic_sent_packet_manager.cc
@@ -535,7 +535,8 @@ bool QuicSentPacketManager::OnPacketSent(
   LOG_IF(DFATAL, bytes == 0) << "Cannot send empty packets.";
 
   if (original_sequence_number == 0) {
-    if (serialized_packet->retransmittable_frames) {
+    if (!FLAGS_quic_ack_notifier_informed_on_serialized &&
+        serialized_packet->retransmittable_frames) {
       ack_notifier_manager_.OnSerializedPacket(*serialized_packet);
     }
   } else {
@@ -946,6 +947,11 @@ QuicPacketCount QuicSentPacketManager::GetSlowStartThresholdInTcpMss() const {
   return send_algorithm_->GetSlowStartThreshold() / kDefaultTCPMSS;
 }
 
+void QuicSentPacketManager::OnSerializedPacket(
+    const SerializedPacket& serialized_packet) {
+  ack_notifier_manager_.OnSerializedPacket(serialized_packet);
+}
+
 void QuicSentPacketManager::EnablePacing() {
   if (using_pacing_) {
     return;