Part of QUIC v39 change: 1) do not ack acks. 2) Send a WINDOW_UPDATE frame every 20 packets which d…

net/quic/core/quic_connection.h

 // Copyright (c) 2012 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.
 //
 // The entity that handles framing writes for a Quic client or server.
 // Each QuicSession will have a connection associated with it.
 //
 // On the server side, the Dispatcher handles the raw reads, and hands off
 // packets via ProcessUdpPacket for framing and processing.
 //
@@ skipping 123 matching lines @@
   virtual void OnConnectionMigration(PeerAddressChangeType type) = 0;
 
   // Called when the peer seems unreachable over the current path.
   virtual void OnPathDegrading() = 0;
 
   // Called after OnStreamFrame, OnRstStream, OnGoAway, OnWindowUpdateFrame,
   // OnBlockedFrame, and OnCanWrite to allow post-processing once the work has
   // been done.
   virtual void PostProcessAfterData() = 0;
 
+  // Called when the connection sends ack after
+  // kMaxConsecutiveNonRetransmittablePackets consecutive not retransmittable
+  // packets sent. To instigate an ack from peer, a retransmittable frame needs
+  // to be added.
+  virtual void OnAckNeedsRetransmittableFrame() = 0;
+
   // Called to ask if the visitor wants to schedule write resumption as it both
   // has pending data to write, and is able to write (e.g. based on flow control
   // limits).
   // Writes may be pending because they were write-blocked, congestion-throttled
   // or yielded to other connections.
   virtual bool WillingAndAbleToWrite() const = 0;
 
   // Called to ask if any handshake messages are pending in this visitor.
   virtual bool HasPendingHandshake() const = 0;
 
@@ skipping 921 matching lines @@
   // Whether a GoAway has been received.
   bool goaway_received_;
 
   // Indicates whether a write error is encountered currently. This is used to
   // avoid infinite write errors.
   bool write_error_occured_;
 
   // Indicates not to send or process stop waiting frames.
   bool no_stop_waiting_frames_;
 
+  // Consecutive number of sent packets which have no retransmittable frames.
+  size_t consecutive_num_packets_with_no_retransmittable_frames_;
+
   DISALLOW_COPY_AND_ASSIGN(QuicConnection);
 };
 
 }  // namespace net
 
 #endif  // NET_QUIC_CORE_QUIC_CONNECTION_H_