diff --git a/common/constants.h b/common/constants.h
index 62f61ce..f9a43c6 100644
--- a/common/constants.h
+++ b/common/constants.h
@@ -50,6 +50,7 @@
 extern const char kPrefsLastActivePingDay[];
 extern const char kPrefsLastRollCallPingDay[];
 extern const char kPrefsManifestMetadataSize[];
+extern const char kPrefsManifestSignatureSize[];
 extern const char kPrefsMetricsAttemptLastReportingTime[];
 extern const char kPrefsMetricsCheckLastReportingTime[];
 extern const char kPrefsNumReboots[];