diff --git a/lib/legacy/class.js b/lib/legacy/class.js
index 6e249b2fa2..bb4326e370 100644
--- a/lib/legacy/class.js
+++ b/lib/legacy/class.js
@@ -197,7 +197,7 @@ function GenerateClassFromInfo(info, Base, behaviors) {
     // explicitly not calling super._finalizeClass
     static _finalizeClass() {
       // if calling via a subclass that hasn't been generated, pass through to super
-      if (!this.hasOwnProperty(window.JSCompiler_renameProperty('generatedFrom', this))) {
+      if (!this.hasOwnProperty(JSCompiler_renameProperty('generatedFrom', this))) {
         super._finalizeClass();
       } else {
         // interleave properties and observers per behavior and `info`