Start using the loss timeout in QuicSentPacketManager and add a mock

net/quic/test_tools/quic_sent_packet_manager_peer.cc

Index: net/quic/test_tools/quic_sent_packet_manager_peer.cc
diff --git a/net/quic/test_tools/quic_sent_packet_manager_peer.cc b/net/quic/test_tools/quic_sent_packet_manager_peer.cc
index ce257640b0697a33f0a556b26fb72a31e7701ec9..be8730f43495f543b6b971d254f08f6cc84dbc83 100644
--- a/net/quic/test_tools/quic_sent_packet_manager_peer.cc
+++ b/net/quic/test_tools/quic_sent_packet_manager_peer.cc
@@ -5,6 +5,7 @@
 #include "net/quic/test_tools/quic_sent_packet_manager_peer.h"
 
 #include "base/stl_util.h"
+#include "net/quic/congestion_control/loss_detection_interface.h"
 #include "net/quic/congestion_control/send_algorithm_interface.h"
 #include "net/quic/quic_protocol.h"
 #include "net/quic/quic_sent_packet_manager.h"
@@ -26,6 +27,13 @@ void QuicSentPacketManagerPeer::SetSendAlgorithm(
 }
 
 // static
+void QuicSentPacketManagerPeer::SetLossAlgorithm(
+    QuicSentPacketManager* sent_packet_manager,
+    LossDetectionInterface* loss_detector) {
+  sent_packet_manager->loss_algorithm_.reset(loss_detector);
+}
+
+// static
 size_t QuicSentPacketManagerPeer::GetNackCount(
     const QuicSentPacketManager* sent_packet_manager,
     QuicPacketSequenceNumber sequence_number) {