diff --git a/api/WindowListener/implementation.js b/api/WindowListener/implementation.js
index c09249e..45bdc81 100644
--- a/api/WindowListener/implementation.js
+++ b/api/WindowListener/implementation.js
@@ -159,11 +159,11 @@ var WindowListener = class extends ExtensionCommon.ExtensionAPI {
     for (let api of apis) {
       switch (api) {
         case "storage":
-          XPCOMUtils.defineLazyGetter(messenger, "storage", () => getStorage());
+          ChromeUtils.defineLazyGetter(messenger, "storage", () => getStorage());
           break;
 
         default:
-          XPCOMUtils.defineLazyGetter(messenger, api, () =>
+          ChromeUtils.defineLazyGetter(messenger, api, () =>
             context.apiCan.findAPIPath(api)
           );
       }