Big merge from experimental to bleeding edge.

samples/sample_extension/sample_asynchronous_extension.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.
 
 library sample_asynchronous_extension;
 
 import 'dart-ext:sample_extension';
 
 // A class caches the native port used to call an asynchronous extension.
 class RandomArray {
   static SendPort _port;
 
   void randomArray(int seed, int length, void callback(List result)) {
-    var args = new List(2);
+    var args = new List.fixedLength(2);
     args[0] = seed;
     args[1] = length;
     _servicePort.call(args).then((result) {
       if (result != null) {
         callback(result);
       } else {
         throw new Exception("Random array creation failed");
       }
     });
   }
 
   SendPort get _servicePort {
     if (_port == null) {
       _port = _newServicePort();
     }
     return _port;
   }
 
   SendPort _newServicePort() native "RandomArray_ServicePort";
 }