Add an IncreaseLargestObserved to QuicUnackedPacketMap to remove the rtt

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 93 matching lines @@
   // Returns the number of unacked packets.
   size_t GetNumUnackedPackets() const;
 
   // Returns true if there are multiple packet pending.
   bool HasMultiplePendingPackets() const;
 
   // Returns true if there are any pending crypto packets.
   bool HasPendingCryptoPackets() const;
 
   // Removes any retransmittable frames from this transmission or an associated
-  // transmission.  It removes any nnon-pending transmissions less than or
-  // equal to |largest_observed|, and disconnects any other packets from other
-  // transmissions.
-  // TODO(ianswett): Remove largest_observed_ once the map tracks whether a
-  // transmission is useful for RTT purposes internally.
-  void RemoveRetransmittability(QuicPacketSequenceNumber sequence_number,
-                                QuicPacketSequenceNumber largest_observed_);
 
-  // Removes an entry from the unacked packet map which is not pending, has
-  // no retransmittable frames, and no associated transmissions.
-  // TODO(ianswett): Remove or make this method private once the map tracks
-  // the three reasons for tracking a packet correctly.
-  void RemoveRttOnlyPacket(QuicPacketSequenceNumber sequence_number);
+  // transmission.  It removes now useless transmissions, and disconnects any
+  // other packets from other transmissions.
+  void RemoveRetransmittability(QuicPacketSequenceNumber sequence_number);
 
-  // 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);
+  // Increases the largest observed.  Any packets less or equal to
+  // |largest_acked_packet| are discarded if they are only for the RTT purposes.
+  void IncreaseLargestObserved(QuicPacketSequenceNumber largest_observed);
 
  private:
   void MaybeRemoveRetransmittableFrames(TransmissionInfo* transmission_info);
 
+  // Returns true if the packet no longer has a purpose in the map.
+  bool IsPacketUseless(UnackedPacketMap::const_iterator it);
+
   QuicPacketSequenceNumber largest_sent_packet_;
+  QuicPacketSequenceNumber largest_observed_;
 
   // 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_