diff --git a/quic/test_tools/quic_connection_peer.cc b/quic/test_tools/quic_connection_peer.cc
index 02775ca..6276b2e 100644
--- a/quic/test_tools/quic_connection_peer.cc
+++ b/quic/test_tools/quic_connection_peer.cc
@@ -308,13 +308,6 @@
 }
 
 // static
-void QuicConnectionPeer::SetSessionDecidesWhatToWrite(
-    QuicConnection* connection) {
-  connection->sent_packet_manager_.SetSessionDecideWhatToWrite(true);
-  connection->packet_generator_.SetCanSetTransmissionType(true);
-}
-
-// static
 void QuicConnectionPeer::SetNegotiatedVersion(QuicConnection* connection) {
   connection->version_negotiated_ = true;
 }
diff --git a/quic/test_tools/quic_connection_peer.h b/quic/test_tools/quic_connection_peer.h
index c5c972f..a0e47ca 100644
--- a/quic/test_tools/quic_connection_peer.h
+++ b/quic/test_tools/quic_connection_peer.h
@@ -127,7 +127,6 @@
                                      bool no_stop_waiting_frames);
   static void SetMaxTrackedPackets(QuicConnection* connection,
                                    QuicPacketCount max_tracked_packets);
-  static void SetSessionDecidesWhatToWrite(QuicConnection* connection);
   static void SetNegotiatedVersion(QuicConnection* connection);
   static void SetMaxConsecutiveNumPacketsWithNoRetransmittableFrames(
       QuicConnection* connection,
diff --git a/quic/test_tools/quic_sent_packet_manager_peer.cc b/quic/test_tools/quic_sent_packet_manager_peer.cc
index b680f66..7b3977e 100644
--- a/quic/test_tools/quic_sent_packet_manager_peer.cc
+++ b/quic/test_tools/quic_sent_packet_manager_peer.cc
@@ -86,18 +86,9 @@
   if (!HasRetransmittableFrames(sent_packet_manager, packet_number)) {
     return false;
   }
-  if (sent_packet_manager->session_decides_what_to_write()) {
-    return sent_packet_manager->unacked_packets_
-               .GetTransmissionInfo(QuicPacketNumber(packet_number))
-               .transmission_type != NOT_RETRANSMISSION;
-  }
-  for (auto transmission_info : sent_packet_manager->unacked_packets_) {
-    if (transmission_info.retransmission.IsInitialized() &&
-        transmission_info.retransmission == QuicPacketNumber(packet_number)) {
-      return true;
-    }
-  }
-  return false;
+  return sent_packet_manager->unacked_packets_
+             .GetTransmissionInfo(QuicPacketNumber(packet_number))
+             .transmission_type != NOT_RETRANSMISSION;
 }
 
 // static
diff --git a/quic/test_tools/quic_test_utils.cc b/quic/test_tools/quic_test_utils.cc
index ff02392..dbc5963 100644
--- a/quic/test_tools/quic_test_utils.cc
+++ b/quic/test_tools/quic_test_utils.cc
@@ -531,7 +531,7 @@
   // Transfer ownership of the packet to the SentPacketManager and the
   // ack notifier to the AckNotifierManager.
   QuicConnectionPeer::GetSentPacketManager(this)->OnPacketSent(
-      packet, QuicPacketNumber(), clock_.ApproximateNow(), NOT_RETRANSMISSION,
+      packet, clock_.ApproximateNow(), NOT_RETRANSMISSION,
       HAS_RETRANSMITTABLE_DATA);
 }
 
diff --git a/quic/test_tools/quic_test_utils.h b/quic/test_tools/quic_test_utils.h
index be6e84d..9f8f23c 100644
--- a/quic/test_tools/quic_test_utils.h
+++ b/quic/test_tools/quic_test_utils.h
@@ -1014,11 +1014,8 @@
 
   MOCK_METHOD1(OnFrameAddedToPacket, void(const QuicFrame&));
 
-  MOCK_METHOD4(OnPacketSent,
-               void(const SerializedPacket&,
-                    QuicPacketNumber,
-                    TransmissionType,
-                    QuicTime));
+  MOCK_METHOD3(OnPacketSent,
+               void(const SerializedPacket&, TransmissionType, QuicTime));
 
   MOCK_METHOD0(OnPingSent, void());
 
diff --git a/quic/test_tools/simple_session_notifier_test.cc b/quic/test_tools/simple_session_notifier_test.cc
index 93f11aa..32dbce4 100644
--- a/quic/test_tools/simple_session_notifier_test.cc
+++ b/quic/test_tools/simple_session_notifier_test.cc
@@ -42,7 +42,6 @@
       : connection_(&helper_, &alarm_factory_, Perspective::IS_CLIENT),
         notifier_(&connection_) {
     connection_.set_visitor(&visitor_);
-    QuicConnectionPeer::SetSessionDecidesWhatToWrite(&connection_);
     EXPECT_FALSE(notifier_.WillingToWrite());
     EXPECT_EQ(0u, notifier_.StreamBytesSent());
     EXPECT_FALSE(notifier_.HasBufferedStreamData());
diff --git a/quic/test_tools/simulator/quic_endpoint.cc b/quic/test_tools/simulator/quic_endpoint.cc
index bd01c43..bf84b37 100644
--- a/quic/test_tools/simulator/quic_endpoint.cc
+++ b/quic/test_tools/simulator/quic_endpoint.cc
@@ -103,9 +103,7 @@
   }
   connection_.SetDataProducer(&producer_);
   connection_.SetSessionNotifier(this);
-  if (connection_.session_decides_what_to_write()) {
-    notifier_ = std::make_unique<test::SimpleSessionNotifier>(&connection_);
-  }
+  notifier_ = std::make_unique<test::SimpleSessionNotifier>(&connection_);
 
   // Configure the connection as if it received a handshake.  This is important
   // primarily because