1 files changed, 1 insertions, 1 deletions
diff --git a/toolkit/components/extensions/test/xpcshell/head_service_worker.js b/toolkit/components/extensions/test/xpcshell/head_service_worker.js
index aa1cf5cb18..771f3b1179 100644
--- a/toolkit/components/extensions/test/xpcshell/head_service_worker.js
+++ b/toolkit/components/extensions/test/xpcshell/head_service_worker.js
@@ -150,7 +150,7 @@ class TestWorkerWatcher extends ExtensionCommon.EventEmitter {
     }
   }
 
-  observe(subject, topic, childIDString) {
+  observe() {
     // Keep the watched process and related test child process actor updated
     // when a process is created or destroyed.
     this.getAndWatchExtensionProcess();