Revert of Uses the activedescendant_changed event received from Blink to fire the right focus event

content/test/data/accessibility/event/menulist-next.html

Index: content/test/data/accessibility/event/menulist-next.html
diff --git a/content/test/data/accessibility/event/menulist-next.html b/content/test/data/accessibility/event/menulist-next.html
index 61ea0676f17269cace69cc82431e1c2cd7c402c7..98d7f3329ab7b025287718150dd3a9841955b56e 100644
--- a/content/test/data/accessibility/event/menulist-next.html
+++ b/content/test/data/accessibility/event/menulist-next.html
@@ -10,12 +10,7 @@
   <option>Banana</option>
 </select>
 <script>
-  var comboBox = document.querySelector('select');
-  comboBox.focus();
-  // Expand the combo box.
-  var clickEvent = document.createEvent('MouseEvents');
-  clickEvent.initMouseEvent('mousedown', true, true, window);
-  comboBox.dispatchEvent(clickEvent);
+  document.querySelector('select').focus();
   function go() {
     document.querySelector('select').selectedIndex = 1;
   }