diff --git a/delta_performer.h b/delta_performer.h
index c693333..7cc1d9b 100644
--- a/delta_performer.h
+++ b/delta_performer.h
@@ -31,6 +31,8 @@
     kMetadataParseInsufficientData,
   };
 
+  static const char kUpdatePayloadPublicKeyPath[];
+
   DeltaPerformer(PrefsInterface* prefs)
       : prefs_(prefs),
         fd_(-1),