diff --git a/platform_constants.h b/platform_constants.h
index 0c832c9..189d134 100644
--- a/platform_constants.h
+++ b/platform_constants.h
@@ -38,6 +38,10 @@
 // whole payload.
 extern const char kUpdatePayloadPublicKeyPath[];
 
+// Path to the file used to notify chrome about the deadline of the last omaha
+// response. Empty if not supported.
+extern const char kOmahaResponseDeadlineFile[];
+
 }  // namespace constants
 }  // namespace chromeos_update_engine