Revert usage of delegating generative constructor, still not supported by VM.

sdk/lib/async/stream.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.
 
 part of dart.async;
 
 // -------------------------------------------------------------------
 // Core Stream types
 // -------------------------------------------------------------------
 
@@ skipping 1655 matching lines @@
 /**
  * An [Iterator] like interface for the values of a [Stream].
  *
  * This wraps a [Stream] and a subscription on the stream. It listens
  * on the stream, and completes the future returned by [moveNext] when the
  * next value becomes available.
  */
 abstract class StreamIterator<T> {
 
   /** Create a [StreamIterator] on [stream]. */
-  factory StreamIterator(Stream<T> stream) = _StreamIteratorImpl<T>;
+  factory StreamIterator(Stream<T> stream)
+      // TODO(lrn): use redirecting factory constructor when type
+      // arguments are supported.
+      => new _StreamIteratorImpl<T>(stream);
 
   /**
    * Wait for the next stream value to be available.
    *
    * Returns a future which will complete with either `true` or `false`.
    * Completing with `true` means that another event has been received and
    * can be read as [current].
    * Completing with `false` means that the stream itearation is done and
    * no further events will ever be available.
    * The future may complete with an error, if the stream produces an error,
@@ skipping 45 matching lines @@
 class _ControllerEventSinkWrapper<T> implements EventSink<T> {
   EventSink _sink;
   _ControllerEventSinkWrapper(this._sink);
 
   void add(T data) { _sink.add(data); }
   void addError(error, [StackTrace stackTrace]) {
     _sink.addError(error, stackTrace);
   }
   void close() { _sink.close(); }
 }