"Fix" dart:js tests in IE9

sdk/lib/js/dart2js/js_dart2js.dart

 // Copyright (c) 2013, 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.
 
 library dart.js;
 
 import 'dart:html' show Blob, ImageData, Node;
 import 'dart:collection' show HashMap;
 import 'dart:indexed_db' show KeyRange;
 import 'dart:typed_data' show TypedData;
@@ skipping 254 matching lines @@
 }
 
 // converts a Dart object to a reference to a native JS object
 // which might be a DartObject JS->Dart proxy
 Object _convertToDart(o) {
   if (JS('bool', '# == null', o) ||
       JS('bool', 'typeof # == "string"', o) ||
       JS('bool', 'typeof # == "number"', o) ||
       JS('bool', 'typeof # == "boolean"', o)) {
     return o;
-  } else if (o is Blob || o is DateTime || o is KeyRange 
-      || o is ImageData || o is Node || o is TypedData) {
-    return JS('Blob|DateTime|KeyRange|ImageData|Node|TypedData', '#', o);
+  } else if (o is Blob || o is KeyRange || o is ImageData || o is Node
+    || o is TypedData) {
+    return JS('Blob|KeyRange|ImageData|Node|TypedData', '#', o);
+  } else if (JS('bool', '# instanceof Date', o)) {
+    var ms = JS('num', '#.getMilliseconds()', o);
+    return new DateTime.fromMillisecondsSinceEpoch(ms);
   } else if (JS('bool', 'typeof # == "function"', o)) {
     return _getDartProxy(o, _DART_CLOSURE_PROPERTY_NAME,
         (o) => new JsFunction._fromJs(o));
   } else if (JS('bool', '#.constructor === DartObject', o)) {
     return JS('', '#.o', o);
   } else {
     return _getDartProxy(o, _DART_OBJECT_PROPERTY_NAME,
         (o) => new JsObject._fromJs(o));
   }
 }
 
 Object _getDartProxy(o, String propertyName, createProxy(o)) {
   var dartProxy = JS('', '#[#]', o, propertyName);
   if (dartProxy == null) {
     dartProxy = createProxy(o);
     _defineProperty(o, propertyName, dartProxy);
   }
   return dartProxy;
 }