diff --git a/common/constants.h b/common/constants.h
index 62f61ce..d001329 100644
--- a/common/constants.h
+++ b/common/constants.h
@@ -93,6 +93,8 @@
 extern const char kPayloadPropertyFileHash[];
 extern const char kPayloadPropertyMetadataSize[];
 extern const char kPayloadPropertyMetadataHash[];
+extern const char kPayloadPropertyAuthorization[];
+extern const char kPayloadPropertyUserAgent[];
 
 // A download source is any combination of protocol and server (that's of
 // interest to us when looking at UMA metrics) using which we may download