--- a/testing/marionette/event.js
+++ b/testing/marionette/event.js
@@ -647,24 +647,16 @@ function emulateToInactivateModifiers_(T
     var event = new KeyboardEvent("", { key: modifiers.lockable[i].key });
     TIP.keydown(event,
       TIP.KEY_NON_PRINTABLE_KEY | TIP.KEY_DONT_DISPATCH_MODIFIER_KEY_EVENT);
     TIP.keyup(event,
       TIP.KEY_NON_PRINTABLE_KEY | TIP.KEY_DONT_DISPATCH_MODIFIER_KEY_EVENT);
   }
 }
 
-function getNavigator_(win = window)
-{
-  if (typeof navigator != "undefined") {
-    return navigator;
-  }
-  return win.navigator;
-}
-
 function isMac_(win = window) {
   if (win) {
     try {
       return win.navigator.platform.indexOf("Mac") > -1;
     } catch (ex) {}
   }
   return navigator.platform.indexOf("Mac") > -1;
 }