--- a/toolkit/components/extensions/ExtensionChild.jsm
+++ b/toolkit/components/extensions/ExtensionChild.jsm
@@ -978,17 +978,17 @@ class DevToolsContextChild extends Exten
     this.extension.devtoolsViews.delete(this);
   }
 }
 
 defineLazyGetter(DevToolsContextChild.prototype, "childManager", function() {
   devtoolsAPIManager.lazyInit();
 
   let localApis = {};
-  let can = new CanOfAPIs(this, apiManager, localApis);
+  let can = new CanOfAPIs(this, devtoolsAPIManager, localApis);
 
   let childManager = new ChildAPIManager(this, this.messageManager, can, {
     envType: "devtools_parent",
     viewType: this.viewType,
     url: this.uri.spec,
     incognito: this.incognito,
   });