diff --git a/constants.h b/constants.h
index 5bba2d3..4f335c3 100644
--- a/constants.h
+++ b/constants.h
@@ -38,6 +38,8 @@
 extern const char kPrefsUpdateStateSignatureBlob[];
 extern const char kPrefsUpdateStateSignedSHA256Context[];
 extern const char kPrefsWallClockWaitPeriod[];
+extern const char kPrefsUpdateTimestampStart[];
+extern const char kPrefsUpdateDurationUptime[];
 
 }  // namespace chromeos_update_engine