Keep an instance of QuicAckFrame in QuicConnection in order to reduce

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 ce3b0010aa578b46dcbce3bcb5af68ff0e559bb9..244fd9c3d35c798d17a51e8387d9231c7cbafe47 100644
--- a/net/quic/quic_connection.cc
+++ b/net/quic/quic_connection.cc
@@ -969,18 +969,16 @@ void QuicConnection::MaybeCloseIfTooManyOutstandingPackets() {
   }
 }
 
-QuicAckFrame* QuicConnection::CreateAckFrame() {
-  QuicAckFrame* outgoing_ack = new QuicAckFrame();
-  received_packet_manager_.UpdateReceivedPacketInfo(
-      outgoing_ack, clock_->ApproximateNow());
-  DVLOG(1) << ENDPOINT << "Creating ack frame: " << *outgoing_ack;
-  return outgoing_ack;
+void QuicConnection::PopulateAckFrame(QuicAckFrame* ack) {
+  received_packet_manager_.UpdateReceivedPacketInfo(ack,
+                                                    clock_->ApproximateNow());
 }
 
-QuicStopWaitingFrame* QuicConnection::CreateStopWaitingFrame() {
-  QuicStopWaitingFrame stop_waiting;
-  UpdateStopWaiting(&stop_waiting);
-  return new QuicStopWaitingFrame(stop_waiting);
+void QuicConnection::PopulateStopWaitingFrame(
+    QuicStopWaitingFrame* stop_waiting) {
+  stop_waiting->least_unacked = GetLeastUnacked();
+  stop_waiting->entropy_hash = sent_entropy_manager_.GetCumulativeEntropy(
+      stop_waiting->least_unacked - 1);
 }
 
 bool QuicConnection::ShouldLastPacketInstigateAck() const {
@@ -1652,12 +1650,6 @@ void QuicConnection::SendOrQueuePacket(QueuedPacket packet) {
   }
 }
 
-void QuicConnection::UpdateStopWaiting(QuicStopWaitingFrame* stop_waiting) {
-  stop_waiting->least_unacked = GetLeastUnacked();
-  stop_waiting->entropy_hash = sent_entropy_manager_.GetCumulativeEntropy(
-      stop_waiting->least_unacked - 1);
-}
-
 void QuicConnection::SendPing() {
   if (retransmission_alarm_->IsSet()) {
     return;