Change QUIC to only ack every other packet when there are no losses

net/quic/quic_received_packet_manager.h

 // Copyright 2013 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.
 //
 // Manages the packet entropy calculation for both sent and received packets
 // for a connection.
 
 #ifndef NET_QUIC_QUIC_RECEIVED_PACKET_MANAGER_H_
 #define NET_QUIC_QUIC_RECEIVED_PACKET_MANAGER_H_
 
@@ skipping 21 matching lines @@
   // bytes: the packet size in bytes including Quic Headers.
   // header: the packet header.
   // timestamp: the arrival time of the packet.
   // revived: true if the packet was lost and then recovered with help of a
   // FEC packet.
   void RecordPacketReceived(QuicByteCount bytes,
                             const QuicPacketHeader& header,
                             QuicTime receipt_time,
                             bool revived);
 
+  // Checks whether |sequence_number| is missing and less than largest observed.
+  bool IsMissing(QuicPacketSequenceNumber sequence_number);
+
   // Checks if we're still waiting for the packet with |sequence_number|.
   bool IsAwaitingPacket(QuicPacketSequenceNumber sequence_number);
 
   // Update the |received_info| for an outgoing ack.
   void UpdateReceivedPacketInfo(ReceivedPacketInfo* received_info,
                                 QuicTime approximate_now);
 
   // Should be called before sending an ACK packet, to decide if we need
   // to attach a QuicCongestionFeedbackFrame block.
   // Returns false if no QuicCongestionFeedbackFrame block is needed.
@@ skipping 10 matching lines @@
   // These two are called by OnAckFrame.
   //
   // Updates internal state based on |incoming_ack.received_info|.
   void UpdatePacketInformationReceivedByPeer(const QuicAckFrame& incoming_ack);
   // Updates internal state based on |incoming_ack.sent_info|.
   void UpdatePacketInformationSentByPeer(const QuicAckFrame& incoming_ack);
 
   // Returns whether the peer is missing packets.
   bool HasMissingPackets();
 
+  // Returns true when there are new missing packets to be reported within 3
+  // packets of the largest observed.
+  bool HasNewMissingPackets();
+
   QuicPacketSequenceNumber peer_largest_observed_packet() {
     return peer_largest_observed_packet_;
   }
 
   QuicPacketSequenceNumber least_packet_awaited_by_peer() {
     return least_packet_awaited_by_peer_;
   }
 
   QuicPacketSequenceNumber peer_least_packet_awaiting_ack() {
     return peer_least_packet_awaiting_ack_;
@@ skipping 55 matching lines @@
   // no sequence numbers have been received since UpdateReceivedPacketInfo.
   // Needed for calculating delta_time_largest_observed.
   QuicTime time_largest_observed_;
 
   scoped_ptr<ReceiveAlgorithmInterface> receive_algorithm_;
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_QUIC_RECEIVED_PACKET_MANAGER_H_