Add a timeout for test_plugin_focus in order for events to be delievered to asynchronous event loops, r=jimm

--HG--
extra : rebase_source : e69cfae5589da8e47585bbd003b6bb8052543712

layout/generic/test/plugin_focus_helper.html

@@ -66,7 +66,7 @@ function handleEvent(event) {
 
   if (s.action) {
     // Do the action after this event cycle is done
-    setTimeout(s.action, 0);
+    setTimeout(s.action, 1000);
   }
 }