Optimize QuicUnackedPacketMap by changing from a LinkedHashMap to a

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 94e46077addb69223de24ba4785e51d6a1f86849..78e9dce3732168fb8a9478592e3f0e20a562c975 100644
--- a/net/quic/test_tools/quic_sent_packet_manager_peer.cc
+++ b/net/quic/test_tools/quic_sent_packet_manager_peer.cc
@@ -120,7 +120,7 @@ size_t QuicSentPacketManagerPeer::GetNumRetransmittablePackets(
   for (QuicUnackedPacketMap::const_iterator it =
            sent_packet_manager->unacked_packets_.begin();
        it != sent_packet_manager->unacked_packets_.end(); ++it) {
-    if (it->second.retransmittable_frames != NULL) {
+    if (it->retransmittable_frames != NULL) {
       ++num_unacked_packets;
     }
   }