1 files changed, 1 insertions, 1 deletions
diff --git a/toolkit/components/pdfjs/test/browser_pdfjs_fullscreen.js b/toolkit/components/pdfjs/test/browser_pdfjs_fullscreen.js
index d53e4cfa74..4add7a4715 100644
--- a/toolkit/components/pdfjs/test/browser_pdfjs_fullscreen.js
+++ b/toolkit/components/pdfjs/test/browser_pdfjs_fullscreen.js
@@ -8,7 +8,7 @@ function waitForFullScreenState(browser, state) {
   return new Promise(resolve => {
     let eventReceived = false;
 
-    let observe = (subject, topic, data) => {
+    let observe = () => {
       if (!eventReceived) {
         return;
       }