isolates refactor: this change introduces 'dart:isolate' as a library. This is a

frog/lib/newisolate.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.
-
-// TODO(sigmund): separate isolates from dart:core
-// #library('dart:isolate');
-
-/**
- * [Isolate2] provides APIs to spawn, communicate, and stop an isolate. An
- * isolate can be spawned by simply creating a new instance of [Isolate2]. The
- * [Isolate2] instance exposes a port to communicate with the isolate and
- * methods to control its behavior remotely.
- */
- // TODO(sigmund): rename to Isolate once we delete the old implementation
-interface Isolate2 default IsolateFactory {
-
-  /**
-   * Create and spawn an isolate that shares the same code as the current
-   * isolate, but that starts from [topLevelFunction]. The [topLevelFunction]
-   * argument must be a static method closure that takes exactly one
-   * argument of type [ReceivePort]. It is illegal to pass a function closure
-   * that captures values in scope.
-   *
-   * When an child isolate is spawned, a new [ReceivePort] is created for it.
-   * This port is passed to [topLevelFunction]. A [SendPort] derived from
-   * such port is sent to the spawner isolate, which is accessible in
-   * [Isolate2.sendPort] field of this instance.
-   */
-  Isolate2.fromCode(Function topLevelFunction);
-
-  /**
-   * Create and spawn an isolate whose code is available at [uri].
-   * The code in [uri] must have an method called [: isolateMain :], which takes
-   * exactly one argument of type [ReceivePort].
-   * Like with [Isolate2.fromCode], a [ReceivePort] is created in the child
-   * isolate, and a [SendPort] to it is stored in [Isolate2.sendPort].
-   */
-  Isolate2.fromUri(String uri);
-
-  /** Port used to communicate with this isolate. */
-  SendPort sendPort;
-
-  /** Stop this isolate. */
-  void stop();
-}
-