Add print closure.

lib/dom/src/native_DOMImplementation.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 class _Utils {
   static List convertToList(List list) {
     // FIXME: [possible optimization]: do not copy the array if Dart_IsArray is fine w/ it.
     final length = list.length;
     List result = new List(length);
     result.setRange(0, length, list);
@@ skipping 14 matching lines @@
 
   static bool isMap(obj) => obj is Map;
 
   static Map createMap() => {};
 
   static makeNotImplementedException(String fileName, int lineNo) {
     return new UnsupportedOperationException('[info: $fileName:$lineNo]');
   }
 
   static window() native "Utils_window";
+  static print(String message) native "Utils_print";
   static SendPort spawnDomFunctionImpl(Function topLevelFunction) native "Utils_spawnDomFunction";
   static int _getNewIsolateId() native "Utils_getNewIsolateId";
 }
 
-Utils_print(String message) native "Utils_print";
-
 class _NPObject extends NativeFieldWrapperClass1 {
   _NPObject();
   static _NPObject retrieve(String key) native "NPObject_retrieve";
   property(String propertyName) native "NPObject_property";
   invoke(String methodName, [ObjectArray args = null]) native "NPObject_invoke";
 }
 
 class _DOMWindowCrossFrameImpl extends NativeFieldWrapperClass1 implements Window {
   _DOMWindowCrossFrameImpl();
 
@@ skipping 47 matching lines @@
   void operator []=(String key, String value) native "DOMStringMap_setItem_Callback";
   String putIfAbsent(String key, String ifAbsent()) => Maps.putIfAbsent(this, key, ifAbsent);
   String remove(String key) native "DOMStringMap_remove_Callback";
   void clear() => Maps.clear(this);
   void forEach(void f(String key, String value)) => Maps.forEach(this, f);
   Collection<String> getKeys() native "DOMStringMap_getKeys_Callback";
   Collection<String> getValues() => Maps.getValues(this);
   int get length() => Maps.length(this);
   bool isEmpty() => Maps.isEmpty(this);
 }
+
+get _printClosure => (s) {
+  try {
+    window.console.log(s);
+  } on Dynamic catch(_) {
+    _Utils.print(s);
+  }
+};