Fix a QUIC bug where a packet could remain in the UnackedPacketMap

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 cffdd4d67edd5d67d6fce65a8f3939130cb7d0de..6dc30a5f9ff5f1a2170f42caa7c93b3b72b22b47 100644
--- a/net/quic/quic_sent_packet_manager.cc
+++ b/net/quic/quic_sent_packet_manager.cc
@@ -172,7 +172,7 @@ void QuicSentPacketManager::HandleAckForSentPackets(
     if (IsAwaitingPacket(received_info, sequence_number)) {
       // Remove any packets not being tracked by the send algorithm, allowing
       // the high water mark to be raised if necessary.
-      if (QuicUnackedPacketMap::IsSentAndNotPending(it->second)) {
+      if (QuicUnackedPacketMap::IsForRttOnly(it->second)) {
         it = MarkPacketHandled(sequence_number, delta_largest_observed);
       } else {
         // Consider it multiple nacks when there is a gap between the missing
@@ -261,8 +261,6 @@ void QuicSentPacketManager::NeuterUnencryptedPackets() {
       // they are not retransmitted or considered lost from a congestion control
       // perspective.
       pending_retransmissions_.erase(it->first);
-      // TODO(ianswett): This may cause packets to linger forever in the
-      // UnackedPacketMap.
       unacked_packets_.NeuterPacket(it->first);
       unacked_packets_.SetNotPending(it->first);
     }