diff --git a/quic/test_tools/quic_framer_peer.h b/quic/test_tools/quic_framer_peer.h
index f6de152..6e34be2 100644
--- a/quic/test_tools/quic_framer_peer.h
+++ b/quic/test_tools/quic_framer_peer.h
@@ -167,6 +167,9 @@
   static void SetExpectedConnectionIDLength(
       QuicFramer* framer,
       uint8_t expected_connection_id_length);
+  static QuicPacketNumber GetLargestDecryptedPacketNumber(
+      QuicFramer* framer,
+      PacketNumberSpace packet_number_space);
 };
 
 }  // namespace test