Very simple version of Isolates.

sdk/lib/_internal/lib/isolate_helper.dart

Index: sdk/lib/_internal/lib/isolate_helper.dart
diff --git a/sdk/lib/_internal/lib/isolate_helper.dart b/sdk/lib/_internal/lib/isolate_helper.dart
index 8b0ad62a9b2a8a245f6367322bb0991617b03f41..0df7db54d0d25ea54660d79319534f0ffb41e9e2 100644
--- a/sdk/lib/_internal/lib/isolate_helper.dart
+++ b/sdk/lib/_internal/lib/isolate_helper.dart
@@ -22,38 +22,6 @@ import 'dart:_interceptors' show JSExtendableArray;
 
 ReceivePort lazyPort;
 
-class CloseToken {
-  /// This token is sent from [IsolateSink]s to [IsolateStream]s to ask them to
-  /// close themselves.
-  const CloseToken();
-}
-
-class JsIsolateSink extends EventSink<dynamic> implements IsolateSink {
-  bool _isClosed = false;
-  final SendPort _port;
-  JsIsolateSink.fromPort(this._port);
-
-  void add(dynamic message) {
-    _port.send(message);
-  }
-
-  void addError(errorEvent) {
-    throw new UnimplementedError("addError on isolate streams");
-  }
-
-  void close() {
-    if (_isClosed) return;
-    add(const CloseToken());
-    _isClosed = true;
-  }
-
-  bool operator==(var other) {
-    return other is IsolateSink && _port == other._port;
-  }
-
-  int get hashCode => _port.hashCode + 499;
-}
-
 /**
  * Called by the compiler to support switching
  * between isolates when we get a callback from the DOM.
@@ -928,14 +896,6 @@ class _PendingSendPortFinder extends _MessageTraverser {
       ports.add(port._futurePort);
     }
   }
-
-  visitIsolateSink(JsIsolateSink sink) {
-    visitSendPort(sink._port);
-  }
-
-  visitCloseToken(CloseToken token) {
-    // Do nothing.
-  }
 }
 
 /********************************************************
@@ -993,16 +953,6 @@ class _JsSerializer extends _Serializer {
           " ports are resolved at this point.";
     }
   }
-
-  visitIsolateSink(JsIsolateSink sink) {
-    SendPort port = sink._port;
-    bool isClosed = sink._isClosed;
-    return ['isolateSink', visitSendPort(port), isClosed];
-  }
-
-  visitCloseToken(CloseToken token) {
-    return ['closeToken'];
-  }
 }
 
 
@@ -1036,18 +986,6 @@ class _JsCopier extends _Copier {
           " ports are resolved at this point.";
     }
   }
-
-  IsolateSink visitIsolateSink(JsIsolateSink sink) {
-    SendPort port = sink._port;
-    bool isClosed = sink._isClosed;
-    JsIsolateSink result = new JsIsolateSink.fromPort(visitSendPort(port));
-    result._isClosed = isClosed;
-    return result;
-  }
-
-  CloseToken visitCloseToken(CloseToken token) {
-    return token;  // Can be shared.
-  }
 }
 
 class _JsDeserializer extends _Deserializer {
@@ -1068,18 +1006,6 @@ class _JsDeserializer extends _Deserializer {
       return new _WorkerSendPort(managerId, isolateId, receivePortId);
     }
   }
-
-  IsolateSink deserializeIsolateSink(List list) {
-    SendPort port = deserializeSendPort(list[1]);
-    bool isClosed = list[2];
-    JsIsolateSink result = new JsIsolateSink.fromPort(port);
-    result._isClosed = isClosed;
-    return result;
-  }
-
-  CloseToken deserializeCloseToken(List list) {
-    return const CloseToken();
-  }
 }
 
 class _JsVisitedMap implements _MessageTraverserVisitedMap {
@@ -1176,9 +1102,6 @@ class _MessageTraverser {
     if (x is List) return visitList(x);
     if (x is Map) return visitMap(x);
     if (x is SendPort) return visitSendPort(x);
-    if (x is SendPortSync) return visitSendPortSync(x);
-    if (x is JsIsolateSink) return visitIsolateSink(x);
-    if (x is CloseToken) return visitCloseToken(x);
 
     // Overridable fallback.
     return visitObject(x);
@@ -1188,9 +1111,6 @@ class _MessageTraverser {
   visitList(List x);
   visitMap(Map x);
   visitSendPort(SendPort x);
-  visitSendPortSync(SendPortSync x);
-  visitIsolateSink(IsolateSink x);
-  visitCloseToken(CloseToken x);
 
   visitObject(Object x) {
     // TODO(floitsch): make this a real exception. (which one)?
@@ -1302,8 +1222,6 @@ class _Deserializer {
       case 'list': return _deserializeList(x);
       case 'map': return _deserializeMap(x);
       case 'sendport': return deserializeSendPort(x);
-      case 'isolateSink': return deserializeIsolateSink(x);
-      case 'closeToken': return deserializeCloseToken(x);
       default: return deserializeObject(x);
     }
   }
@@ -1345,10 +1263,6 @@ class _Deserializer {
 
   deserializeSendPort(List x);
 
-  deserializeIsolateSink(List x);
-
-  deserializeCloseToken(List x);
-
   deserializeObject(List x) {
     // TODO(floitsch): Use real exception (which one?).
     throw "Unexpected serialized object";