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

net/quic/quic_unacked_packet_map.h

 // Copyright 2014 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_
 #define NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_
 
 #include "net/base/linked_hash_map.h"
 #include "net/quic/quic_protocol.h"
 
@@ skipping 104 matching lines @@
 
   // Removes entries from the unacked packet map, and deletes
   // the retransmittable frames associated with the packet.
   // Does not remove any previous or subsequent transmissions of this packet.
   void RemovePacket(QuicPacketSequenceNumber sequence_number);
 
   // Neuters the specified packet.  Deletes any retransmittable
   // frames, and sets all_transmissions to only include itself.
   void NeuterPacket(QuicPacketSequenceNumber sequence_number);
 
-  // Returns true if the packet has been marked as sent by SetSent.
-  static bool IsSentAndNotPending(const TransmissionInfo& transmission_info);
+  // Returns true if the packet's only purpose is to measure RTT.  It must not
+  // be pending, have retransmittable frames, or be linked to transmissions
+  // with retransmittable frames.
+  static bool IsForRttOnly(const TransmissionInfo& transmission_info);
 
  private:
   void MaybeRemoveRetransmittableFrames(TransmissionInfo* transmission_info);
 
   QuicPacketSequenceNumber largest_sent_packet_;
 
   // Newly serialized retransmittable and fec packets are added to this map,
   // which contains owning pointers to any contained frames.  If a packet is
   // retransmitted, this map will contain entries for both the old and the new
   // packet. The old packet's retransmittable frames entry will be NULL, while
   // the new packet's entry will contain the frames to retransmit.
   // If the old packet is acked before the new packet, then the old entry will
   // be removed from the map and the new entry's retransmittable frames will be
   // set to NULL.
   UnackedPacketMap unacked_packets_;
 
   size_t bytes_in_flight_;
   // Number of outstanding crypto handshake packets.
   size_t pending_crypto_packet_count_;
 
   DISALLOW_COPY_AND_ASSIGN(QuicUnackedPacketMap);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_UNACKED_PACKET_MAP_H_