Deprecate FLAGS_quic_always_write_queued_retransmissions.

net/quic/quic_connection.cc

 // 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.
 
 #include "net/quic/quic_connection.h"
 
 #include <string.h>
 #include <sys/types.h>
 
 #include <algorithm>
@@ skipping 1730 matching lines @@
   QuicPacketNumber packet_number = packet.packet_number;
   if (encryption_level_ == ENCRYPTION_FORWARD_SECURE &&
       packet.encryption_level == ENCRYPTION_NONE) {
     // Drop packets that are NULL encrypted since the peer won't accept them
     // anymore.
     DVLOG(1) << ENDPOINT << "Dropping NULL encrypted packet: " << packet_number
              << " since the connection is forward secure.";
     return true;
   }
 
-  // TODO(fayang): Remove IsUnacked and HasRetransmittableFrames from
-  // QuicSentPacketManagerInterface when deprecating
-  // gfe2_reloadable_flag_quic_always_write_queued_retransmissions.
-  if (FLAGS_quic_always_write_queued_retransmissions) {
-    return false;
-  }
-
-  // If a retransmission has been acked before sending, don't send it.
-  // This occurs if a packet gets serialized, queued, then discarded.
-  if (packet.transmission_type != NOT_RETRANSMISSION &&
-      (!sent_packet_manager_->IsUnacked(packet.original_path_id,
-                                        packet.original_packet_number) ||
-       !sent_packet_manager_->HasRetransmittableFrames(
-           packet.original_path_id, packet.original_packet_number))) {
-    DVLOG(1) << ENDPOINT << "Dropping unacked packet: " << packet_number
-             << " A previous transmission was acked while write blocked.";
-    return true;
-  }
-
   return false;
 }
 
 void QuicConnection::OnWriteError(int error_code) {
   const string error_details = "Write failed with error: " +
                                base::IntToString(error_code) + " (" +
                                ErrorToString(error_code) + ")";
   DVLOG(1) << ENDPOINT << error_details;
   // We can't send an error as the socket is presumably borked.
   TearDownLocalConnectionState(QUIC_PACKET_WRITE_ERROR, error_details,
@@ skipping 733 matching lines @@
 // the sender and a signaling mechanism -- if the sender uses a
 // different MinRTO, we may get spurious retransmissions. May not have
 // any benefits, but if the delayed ack becomes a significant source
 // of (likely, tail) latency, then consider such a mechanism.
 const QuicTime::Delta QuicConnection::DelayedAckTime() {
   return QuicTime::Delta::FromMilliseconds(
       min(kMaxDelayedAckTimeMs, kMinRetransmissionTimeMs / 2));
 }
 
 }  // namespace net