Change some of QUIC's AckNotifier datastructures from maps to hashmaps

net/quic/quic_ack_notifier_manager.cc

Index: net/quic/quic_ack_notifier_manager.cc
diff --git a/net/quic/quic_ack_notifier_manager.cc b/net/quic/quic_ack_notifier_manager.cc
index 129a951e8940d6daa1d1c975a8582bbd92ccf1b0..39db3f2fe48e4a990b336061fbd90390630b9114 100644
--- a/net/quic/quic_ack_notifier_manager.cc
+++ b/net/quic/quic_ack_notifier_manager.cc
@@ -34,8 +34,8 @@ void AckNotifierManager::OnPacketAcked(QuicPacketSequenceNumber sequence_number,
 
   // One or more AckNotifiers are registered as interested in this sequence
   // number. Iterate through them and call OnAck on each.
-  AckNotifierSet& ack_notifier_set = map_it->second;
-  for (QuicAckNotifier* ack_notifier : ack_notifier_set) {
+  AckNotifierList& ack_notifier_list = map_it->second;
+  for (QuicAckNotifier* ack_notifier : ack_notifier_list) {
     ack_notifier->OnAck(sequence_number, delta_largest_observed);
 
     // If this has resulted in an empty AckNotifer, erase it.
@@ -60,15 +60,15 @@ void AckNotifierManager::UpdateSequenceNumber(
   }
 
   // Update the existing QuicAckNotifiers to the new sequence number.
-  AckNotifierSet& ack_notifier_set = map_it->second;
-  for (QuicAckNotifier* ack_notifier : ack_notifier_set) {
+  AckNotifierList& ack_notifier_list = map_it->second;
+  for (QuicAckNotifier* ack_notifier : ack_notifier_list) {
     ack_notifier->UpdateSequenceNumber(old_sequence_number,
                                        new_sequence_number);
   }
 
   // The old sequence number is no longer of interest, copy the updated
   // AckNotifiers to the new sequence number before deleting the old.
-  ack_notifier_map_[new_sequence_number] = ack_notifier_set;
+  ack_notifier_map_[new_sequence_number] = ack_notifier_list;
   ack_notifier_map_.erase(map_it);
 }
 
@@ -86,7 +86,7 @@ void AckNotifierManager::OnSerializedPacket(
 
       // Update the mapping in the other direction, from sequence number to
       // AckNotifier.
-      ack_notifier_map_[serialized_packet.sequence_number].insert(notifier);
+      ack_notifier_map_[serialized_packet.sequence_number].push_back(notifier);
 
       // Take ownership of the AckNotifier.
       ack_notifiers_.insert(notifier);
@@ -112,7 +112,7 @@ void AckNotifierManager::OnSerializedPacket(
 
       // Update the mapping in the other direction, from sequence number to
       // AckNotifier.
-      ack_notifier_map_[serialized_packet.sequence_number].insert(notifier);
+      ack_notifier_map_[serialized_packet.sequence_number].push_back(notifier);
 
       // Take ownership of the AckNotifier.
       ack_notifiers_.insert(notifier);