Replace the map in QuicAckNotifier with a counter.

net/quic/quic_ack_notifier_manager.h

Index: net/quic/quic_ack_notifier_manager.h
diff --git a/net/quic/quic_ack_notifier_manager.h b/net/quic/quic_ack_notifier_manager.h
index 4fc8b3d5403545dd6537d5e81e5ea56a58865045..bf4d574f2431d62cb74a2db7e1debd617ae43fbf 100644
--- a/net/quic/quic_ack_notifier_manager.h
+++ b/net/quic/quic_ack_notifier_manager.h
@@ -35,8 +35,9 @@ class NET_EXPORT_PRIVATE AckNotifierManager {
   // If a packet has been retransmitted with a new sequence number, then this
   // will be called. It updates the mapping in ack_notifier_map_, and also
   // updates the internal set of sequence numbers in each matching AckNotifier.
-  void UpdateSequenceNumber(QuicPacketSequenceNumber old_sequence_number,
-                            QuicPacketSequenceNumber new_sequence_number);
+  void OnPacketRetransmitted(QuicPacketSequenceNumber old_sequence_number,
+                             QuicPacketSequenceNumber new_sequence_number,
+                             int packet_payload_size);
 
   // This is called after a packet has been serialized, is ready to be sent, and
   // contains retransmittable frames (which may have associated AckNotifiers).