1 files changed, 1 insertions, 1 deletions
diff --git a/toolkit/mozapps/extensions/test/xpcshell/test_install_cancel.js b/toolkit/mozapps/extensions/test/xpcshell/test_install_cancel.js
index 0be6ec0359..b5902bc6ba 100644
--- a/toolkit/mozapps/extensions/test/xpcshell/test_install_cancel.js
+++ b/toolkit/mozapps/extensions/test/xpcshell/test_install_cancel.js
@@ -35,7 +35,7 @@ class TestListener {
 
 function startListener(listener) {
   let observer = {
-    observe(subject, topic, data) {
+    observe(subject) {
       let channel = subject.QueryInterface(Ci.nsIHttpChannel);
       if (channel.URI.spec === "http://example.com/addons/test.xpi") {
         let channelListener = new TestListener(listener);