diff --git a/resources/externs/main.js b/resources/externs/main.js
index be5aed904c..1e3d5eb8c7 100644
--- a/resources/externs/main.js
+++ b/resources/externs/main.js
@@ -25,5 +25,8 @@ var TopLevel = {
   "value": function() {},
   "identifier": function() {},
   "getBoundingClientRect": function() {},
-  "getBBox": function() {}
+  "getBBox": function() {},
+  "addEventListener": function() {},
+  "postMessage": function() {},
+  "data": function() {}
 };