diff --git a/quic/core/quic_packets.h b/quic/core/quic_packets.h
index d2aaf34..509fd08 100644
--- a/quic/core/quic_packets.h
+++ b/quic/core/quic_packets.h
@@ -140,7 +140,7 @@
   // An arbitrary string to identify an endpoint. Used by clients to
   // differentiate traffic from Google servers vs Non-google servers.
   // Will not be used if empty().
-  QuicString endpoint_id;
+  std::string endpoint_id;
 };
 
 struct QUIC_EXPORT_PRIVATE QuicVersionNegotiationPacket {