Refactor QuicConnection's async write behavior to record a packet as

net/quic/quic_connection.cc

Index: net/quic/quic_connection.cc
diff --git a/net/quic/quic_connection.cc b/net/quic/quic_connection.cc
index d6ea19e57624b2874849ec15e27d7c4f31061c8e..182bd301f71d097d79a41b9c5d5d7fe7091534fc 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -1389,9 +1389,6 @@ bool QuicConnection::WritePacket(QueuedPacket packet) {
       << packet.packet->length() << " " << encrypted->length() << " "
       << " close: " << (packet.type == CONNECTION_CLOSE ? "yes" : "no");
 
-  DCHECK(pending_write_.get() == NULL);
-  pending_write_.reset(new QueuedPacket(packet));
-
   WriteResult result = writer_->WritePacket(encrypted->data(),
                                             encrypted->length(),
                                             self_address().address(),
@@ -1407,23 +1404,52 @@ bool QuicConnection::WritePacket(QueuedPacket packet) {
                                  *encrypted,
                                  result);
   }
+
   if (result.status == WRITE_STATUS_BLOCKED) {
     visitor_->OnWriteBlocked();
     // If the socket buffers the the data, then the packet should not
     // be queued and sent again, which would result in an unnecessary
     // duplicate packet being sent.  The helper must call OnPacketSent
     // when the packet is actually sent.
-    if (writer_->IsWriteBlockedDataBuffered()) {
-      return true;
+    if (!writer_->IsWriteBlockedDataBuffered()) {
+      return false;
     }
-    pending_write_.reset();
-    return false;
   }
+  QuicTime now = clock_->Now();
+  if (packet.transmission_type == NOT_RETRANSMISSION) {
+    time_of_last_sent_new_packet_ = now;
+  }
+  SetPingAlarm();
+  DVLOG(1) << ENDPOINT << "time of last sent packet: "
+           << now.ToDebuggingValue();
 
-  if (OnPacketSent(result)) {
-    return true;
+  // TODO(ianswett): Change the sequence number length and other packet creator
+  // options by a more explicit API than setting a struct value directly,
+  // perhaps via the NetworkChangeVisitor.
+  packet_generator_.UpdateSequenceNumberLength(
+      sent_packet_manager_.least_packet_awaited_by_peer(),
+      sent_packet_manager_.GetCongestionWindow());
+
+  bool reset_retransmission_alarm =
+      sent_packet_manager_.OnPacketSent(sequence_number,
+                                        now,
+                                        encrypted->length(),
+                                        packet.transmission_type,
+                                        packet.retransmittable);
+
+  if (reset_retransmission_alarm || !retransmission_alarm_->IsSet()) {
+    retransmission_alarm_->Update(sent_packet_manager_.GetRetransmissionTime(),
+                                  QuicTime::Delta::FromMilliseconds(1));
   }
-  return false;
+
+  stats_.bytes_sent += result.bytes_written;
+  ++stats_.packets_sent;
+  if (packet.transmission_type != NOT_RETRANSMISSION) {
+    stats_.bytes_retransmitted += result.bytes_written;
+    ++stats_.packets_retransmitted;
+  }
+
+  return OnPacketSent(result);
 }
 
 bool QuicConnection::ShouldDiscardPacket(
@@ -1468,18 +1494,6 @@ bool QuicConnection::ShouldDiscardPacket(
 }
 
 bool QuicConnection::OnPacketSent(WriteResult result) {
-  DCHECK_NE(WRITE_STATUS_BLOCKED, result.status);
-  if (pending_write_.get() == NULL) {
-    LOG(DFATAL) << "OnPacketSent called without a pending write.";
-    return false;
-  }
-
-  QuicPacketSequenceNumber sequence_number = pending_write_->sequence_number;
-  TransmissionType transmission_type  = pending_write_->transmission_type;
-  HasRetransmittableData retransmittable = pending_write_->retransmittable;
-  size_t length = pending_write_->length;
-  pending_write_.reset();
-
   if (result.status == WRITE_STATUS_ERROR) {
     DVLOG(1) << ENDPOINT << "Write failed with error: " << result.error_code
              << " (" << ErrorToString(result.error_code) << ")";
@@ -1488,38 +1502,6 @@ bool QuicConnection::OnPacketSent(WriteResult result) {
     return false;
   }
 
-  QuicTime now = clock_->Now();
-  if (transmission_type == NOT_RETRANSMISSION) {
-    time_of_last_sent_new_packet_ = now;
-  }
-  SetPingAlarm();
-  DVLOG(1) << ENDPOINT << "time of last sent packet: "
-           << now.ToDebuggingValue();
-
-  // TODO(ianswett): Change the sequence number length and other packet creator
-  // options by a more explicit API than setting a struct value directly.
-  packet_generator_.UpdateSequenceNumberLength(
-      sent_packet_manager_.least_packet_awaited_by_peer(),
-      sent_packet_manager_.GetCongestionWindow());
-
-  bool reset_retransmission_alarm =
-      sent_packet_manager_.OnPacketSent(sequence_number, now, length,
-                                        transmission_type, retransmittable);
-
-  if (reset_retransmission_alarm || !retransmission_alarm_->IsSet()) {
-    QuicTime retransmission_time = sent_packet_manager_.GetRetransmissionTime();
-    retransmission_alarm_->Update(retransmission_time,
-                                  QuicTime::Delta::FromMilliseconds(1));
-  }
-
-  stats_.bytes_sent += result.bytes_written;
-  ++stats_.packets_sent;
-
-  if (transmission_type != NOT_RETRANSMISSION) {
-    stats_.bytes_retransmitted += result.bytes_written;
-    ++stats_.packets_retransmitted;
-  }
-
   return true;
 }