Don't copy the QuicAckFrame into the QuicPacketGenerator. Protected by quic_dont_copy_acks.

net/quic/test_tools/quic_connection_peer.h

Index: net/quic/test_tools/quic_connection_peer.h
diff --git a/net/quic/test_tools/quic_connection_peer.h b/net/quic/test_tools/quic_connection_peer.h
index d547dc46fb057827db9dd9f7b37f9122578b01f4..535f70f4243e7278edc17c430ec23d6fbf01ffce 100644
--- a/net/quic/test_tools/quic_connection_peer.h
+++ b/net/quic/test_tools/quic_connection_peer.h
@@ -40,6 +40,8 @@ class QuicConnectionPeer {
 
   static void PopulateAckFrame(QuicConnection* connection, QuicAckFrame* ack);
 
+  static const QuicFrame GetUpdatedAckFrame(QuicConnection* connection);
+
   static void PopulateStopWaitingFrame(QuicConnection* connection,
                                        QuicStopWaitingFrame* stop_waiting);