Remove Sink and move CollectionSink to async.

sdk/lib/async/stream.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 dart.async;
 
 // -------------------------------------------------------------------
 // Core Stream types
 // -------------------------------------------------------------------
 
@@ skipping 197 matching lines @@
         result._setError(e);
       },
       onDone: () {
         result._setValue(value);
       },
       unsubscribeOnError: true);
     return result;
   }
 
   // Deprecated method, previously called 'pipe', retained for compatibility.
-  Future pipeInto(Sink<T> sink,
+  Future pipeInto(StreamSink<T> sink,
                   {void onError(AsyncError error),
                    bool unsubscribeOnError}) {
     _FutureImpl<T> result = new _FutureImpl<T>();
     this.listen(
         sink.add,
-        onError: onError,
+        onError: sink.signalError,
         onDone: () {
           sink.close();
           result._setValue(null);
         },
         unsubscribeOnError: unsubscribeOnError);
     return result;
   }
 
 
   /**
@@ skipping 605 matching lines @@
   /**
    * Resume after a pause.
    */
   void resume();
 }
 
 
 /**
  * An interface that abstracts sending events into a [Stream].
  */
-abstract class StreamSink<T> implements Sink<T> {
+abstract class StreamSink<T> {
   void add(T event);
   /** Signal an async error to the receivers of this sink's values. */
   void signalError(AsyncError errorEvent);
   void close();
 }
 
 /** [Stream] wrapper that only exposes the [Stream] interface. */
 class StreamView<T> extends Stream<T> {
   Stream<T> _stream;
 
@@ skipping 250 matching lines @@
 }
 
 class _StreamOutputSinkWrapper<T> implements StreamSink<T> {
   _StreamOutputSink _sink;
   _StreamOutputSinkWrapper(this._sink);
 
   void add(T data) => _sink._sendData(data);
   void signalError(AsyncError error) => _sink._sendError(error);
   void close() => _sink._sendDone();
 }