Isolates: allow sending of arbitrary objects in dart2js.

sdk/lib/_internal/compiler/js_lib/native_helper.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.
 
 part of _js_helper;
 
 
 // TODO(ngeoffray): stop using this method once our optimizers can
 // change str1.contains(str2) into str1.indexOf(str2) != -1.
 bool contains(String userAgent, String name) {
@@ skipping 425 matching lines @@
 //
 // This is a temporary place for the JavaScript code.
 //
 // TODO(sra): These code fragments are not minified.  They could be generated by
 // the code emitter, or JS_CONST could be improved to parse entire functions and
 // take care of the minification.
 
 const _baseHooks = const JS_CONST(r'''
 function() {
   function typeNameInChrome(o) {
-    var name = o.constructor.name;
-    if (name) return name;
+    var constructor = o.constructor;
+    if (constructor) {
+      var name = constructor.name;
+      if (name) return name;
+    }
     var s = Object.prototype.toString.call(o);
     return s.substring(8, s.length - 1);
   }
   function getUnknownTag(object, tag) {
     // This code really belongs in [getUnknownTagGenericBrowser] but having it
     // here allows [getUnknownTag] to be tested on d8.
     if (/^HTML[A-Z].*Element$/.test(tag)) {
       // Check that it is not a simple JavaScript object.
       var name = Object.prototype.toString.call(object);
       if (name == "[object Object]") return null;
@@ skipping 181 matching lines @@
 const _safariHooksTransformer = const JS_CONST(r'''
 function(hooks) { return hooks; }
 ''');
 
 
 const _dartExperimentalFixupGetTagHooksTransformer = const JS_CONST(r'''
 function(hooks) {
   if (typeof dartExperimentalFixupGetTag != "function") return hooks;
   hooks.getTag = dartExperimentalFixupGetTag(hooks.getTag);
 }''');