Add Isolate.current getter, returning the current isolate as an Isolate object.

sdk/lib/isolate/isolate.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.
 
 /**
  * Concurrent programming using _isolates_:
  * independent workers that are similar to threads
  * but don't share memory,
  * communicating only via messages.
  */
@@ skipping 102 matching lines @@
    *
    * If all the available capabilities are included,
    * there is no reason to create a new object,
    * since the behavior is defined entirely
    * by the control port and capabilities.
    */
   Isolate(this.controlPort, {this.pauseCapability,
                              this.terminateCapability});
 
   /**
+   * Return the current [Isolate].
+   *
+   * The isolate gives access to the capabilities needed to inspect,
+   * pause or kill the isolate, and allows granting these capabilities
+   * to others.
+   */
+  external static Isolate get current;
+
+  /**
    * Creates and spawns an isolate that shares the same code as the current
    * isolate.
    *
    * The argument [entryPoint] specifies the entry point of the spawned
    * isolate. It must be a top-level function or a static method that
    * takes one argument - that is, one-parameter functions that can be
    * compile-time constant function values.
    * It is not allowed to pass the value of function expressions or an instance
    * method extracted from an object.
    *
@@ skipping 467 matching lines @@
       : _description = description,
         stackTrace = new _RemoteStackTrace(stackDescription);
   String toString() => _description;
 }
 
 class _RemoteStackTrace implements StackTrace {
   String _trace;
   _RemoteStackTrace(this._trace);
   String toString() => _trace;
 }