diff --git a/quic/core/quic_crypto_stream.h b/quic/core/quic_crypto_stream.h
index d2a729e..e60277b 100644
--- a/quic/core/quic_crypto_stream.h
+++ b/quic/core/quic_crypto_stream.h
@@ -63,7 +63,7 @@
   bool ExportKeyingMaterial(QuicStringPiece label,
                             QuicStringPiece context,
                             size_t result_len,
-                            QuicString* result) const;
+                            std::string* result) const;
 
   // Writes |data| to the QuicStream at level |level|.
   virtual void WriteCryptoData(EncryptionLevel level, QuicStringPiece data);