Make wpt keyboard-accesskey-click-event.html pass on Mac

Gecko use the same combination as other browsers to trigger accesskey.

Differential Revision: https://phabricator.services.mozilla.com/D109369

bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1700138
gecko-commit: da2e43cf58784b1c24c4e58a52066d71d6ee9b85
gecko-reviewers: masayuki
diff --git a/uievents/interface/keyboard-accesskey-click-event.html b/uievents/interface/keyboard-accesskey-click-event.html
index 74c6410..fa1dc12 100644
--- a/uievents/interface/keyboard-accesskey-click-event.html
+++ b/uievents/interface/keyboard-accesskey-click-event.html
@@ -53,18 +53,12 @@
   // There are differences in using accesskey across browsers and OS's.
   // See: // https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/accesskey
   let isMacOSX = navigator.userAgent.indexOf("Mac") != -1;
-  let isFirefox = navigator.userAgent.toLowerCase().indexOf('firefox') > -1;
   // Default OS access keys.
   let osAccessKey = [shiftKey, altKey];
   // Set the OS keys that need to be pressed for a keyboard accessibility click.
   if(isMacOSX){
-    if(isFirefox){
-      // On Firefox on Mac use Shift + Option + accesskey.
-      osAccessKey = [shiftKey, optionKey];
-    }else{
-      // On Mac use Control + Option + accesskey (for button is g).
-      osAccessKey = [controlKey, optionKey];
-    }
+    // On Mac use Control + Option + accesskey (for button is g).
+    osAccessKey = [controlKey, optionKey];
   }
   // Press keys.
   for(key of osAccessKey)