diff --git a/quic/core/quic_session.h b/quic/core/quic_session.h
index 9233402..92c4082 100644
--- a/quic/core/quic_session.h
+++ b/quic/core/quic_session.h
@@ -714,7 +714,7 @@
 
   // Keep track of highest received byte offset of locally closed streams, while
   // waiting for a definitive final highest offset from the peer.
-  std::map<QuicStreamId, QuicStreamOffset>
+  QuicHashMap<QuicStreamId, QuicStreamOffset>
       locally_closed_streams_highest_offset_;
 
   QuicConnection* connection_;
diff --git a/quic/test_tools/quic_session_peer.cc b/quic/test_tools/quic_session_peer.cc
index ea9dc06..6823691 100644
--- a/quic/test_tools/quic_session_peer.cc
+++ b/quic/test_tools/quic_session_peer.cc
@@ -120,7 +120,7 @@
 }
 
 // static
-std::map<QuicStreamId, QuicStreamOffset>&
+QuicHashMap<QuicStreamId, QuicStreamOffset>&
 QuicSessionPeer::GetLocallyClosedStreamsHighestOffset(QuicSession* session) {
   return session->locally_closed_streams_highest_offset_;
 }
diff --git a/quic/test_tools/quic_session_peer.h b/quic/test_tools/quic_session_peer.h
index 061f16d..1366ddb 100644
--- a/quic/test_tools/quic_session_peer.h
+++ b/quic/test_tools/quic_session_peer.h
@@ -54,7 +54,7 @@
   static QuicWriteBlockedList* GetWriteBlockedStreams(QuicSession* session);
   static QuicStream* GetOrCreateStream(QuicSession* session,
                                        QuicStreamId stream_id);
-  static std::map<QuicStreamId, QuicStreamOffset>&
+  static QuicHashMap<QuicStreamId, QuicStreamOffset>&
   GetLocallyClosedStreamsHighestOffset(QuicSession* session);
   static QuicSession::StreamMap& stream_map(QuicSession* session);
   static const QuicSession::ClosedStreams& closed_streams(QuicSession* session);