dart:html perf optimization based on runing Dromaeo benchmarks

lib/dom/templates/html/dartium/impl_EventTarget.darttemplate

Index: lib/dom/templates/html/dartium/impl_EventTarget.darttemplate
diff --git a/lib/dom/templates/html/dartium/impl_EventTarget.darttemplate b/lib/dom/templates/html/dartium/impl_EventTarget.darttemplate
index 651758c0b03542666d7f4b04faddf7183644624e..18b73540d74f0d719c2ffc14627cebb2d557efb4 100644
--- a/lib/dom/templates/html/dartium/impl_EventTarget.darttemplate
+++ b/lib/dom/templates/html/dartium/impl_EventTarget.darttemplate
@@ -50,11 +50,11 @@ class _EventListenerListImpl implements EventListenerList {
     // TODO(jacobr): what is the correct behavior here. We could alternately
     // force the event to have the expected type.
     assert(evt.type == _type);
-    return _ptr._dispatchEvent(evt);
+    return _ptr.$dom_dispatchEvent(evt);
   }
 
   void _add(EventListener listener, bool useCapture) {
-    _ptr._addEventListener(_type,
+    _ptr.$dom_addEventListener(_type,
                           _findOrAddWrapper(listener, useCapture),
                           useCapture);
   }
@@ -62,7 +62,7 @@ class _EventListenerListImpl implements EventListenerList {
   void _remove(EventListener listener, bool useCapture) {
     Function wrapper = _removeWrapper(listener, useCapture);
     if (wrapper !== null) {
-      _ptr._removeEventListener(_type, wrapper, useCapture);
+      _ptr.$dom_removeEventListener(_type, wrapper, useCapture);
     }
   }