Backed out 2 changesets (bug 1141498) for mochitest-1 bustage

Backed out changeset aab01fe57d48 (bug 1141498)
Backed out changeset d366dc0fb693 (bug 1141498)

dom/animation/test/testcommon.js

@@ -7,22 +7,12 @@
  * @param t  The testharness.js Test object. If provided, this will be used
  *           to register a cleanup callback to remove the div when the test
  *           finishes.
- *
- * @param attrs  A dictionary object with attribute names and values to set on
- *               the div.
  */
-function addDiv(t, attrs) {
+function addDiv(t) {
   var div = document.createElement('div');
-  if (attrs) {
-    for (var attrName in attrs) {
-      div.setAttribute(attrName, attrs[attrName]);
-    }
-  }
   document.body.appendChild(div);
   if (t && typeof t.add_cleanup === 'function') {
-    t.add_cleanup(function() {
-      div.parentNode.removeChild(div);
-    });
+    t.add_cleanup(function() { div.remove(); });
   }
   return div;
 }