Keep an instance of QuicAckFrame in QuicConnection in order to reduce

net/quic/quic_connection_test.cc

Index: net/quic/quic_connection_test.cc
diff --git a/net/quic/quic_connection_test.cc b/net/quic/quic_connection_test.cc
index 091dc9ec86df1633ed9a77efbb0ea3c93a1e5618..47588d0f060e0ac7475b3d8d79430ffc3e38d905 100644
--- a/net/quic/quic_connection_test.cc
+++ b/net/quic/quic_connection_test.cc
@@ -662,14 +662,13 @@ class QuicConnectionTest : public ::testing::TestWithParam<QuicVersion> {
   }
 
   QuicAckFrame* outgoing_ack() {
-    outgoing_ack_.reset(QuicConnectionPeer::CreateAckFrame(&connection_));
-    return outgoing_ack_.get();
+    QuicConnectionPeer::PopulateAckFrame(&connection_, &ack_);
+    return &ack_;
   }
 
   QuicStopWaitingFrame* stop_waiting() {
-    stop_waiting_.reset(
-        QuicConnectionPeer::CreateStopWaitingFrame(&connection_));
-    return stop_waiting_.get();
+    QuicConnectionPeer::PopulateStopWaitingFrame(&connection_, &stop_waiting_);
+    return &stop_waiting_;
   }
 
   QuicPacketSequenceNumber least_unacked() {
@@ -1006,8 +1005,8 @@ class QuicConnectionTest : public ::testing::TestWithParam<QuicVersion> {
   QuicPacketHeader header_;
   QuicStreamFrame frame1_;
   QuicStreamFrame frame2_;
-  scoped_ptr<QuicAckFrame> outgoing_ack_;
-  scoped_ptr<QuicStopWaitingFrame> stop_waiting_;
+  QuicAckFrame ack_;
+  QuicStopWaitingFrame stop_waiting_;
   QuicSequenceNumberLength sequence_number_length_;
   QuicConnectionIdLength connection_id_length_;