Fix bad handling of done events in _ForwardingStream.

tests/lib/async/stream_transform_test.dart

+// Copyright (c) 2011, 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.
+
+library stream_transform_test;
+
+import 'dart:async';
+import '../../../pkg/unittest/lib/unittest.dart';
+import 'event_helper.dart';
+
+
+main() {
+  // Regression tests for http://dartbug.com/8311
+
+  test("simpleDone", () {
+    StreamController c = new StreamController();
+    Stream out = c.stream.handleError((x){}).handleError((x){});
+    out.listen((v){}, onDone: expectAsync0(() {}));
+    // Should not throw.
+    c.close();
+  });
+
+  test("with events", () {
+    StreamController c = new StreamController();
+    Events expected = new Events.fromIterable([10, 12]);
+    Events input = new Events.fromIterable([1, 2, 3, 4, 5, 6, 7]);
+    Events actual = new Events.capture(
+        c.stream.map((x) => x * 2).where((x) => x > 5).skip(2).take(2));
+    actual.onDone(expectAsync0(() {
+      Expect.listEquals(expected.events, actual.events);
+    }));
+    input.replay(c);
+  });
+
+  test("paused events", () {
+    StreamController c = new StreamController();
+    Events expected = new Events.fromIterable([10, 12]);
+    Events input = new Events.fromIterable([1, 2, 3, 4, 5, 6, 7]);
+    Events actual = new Events.capture(
+        c.stream.map((x) => x * 2).where((x) => x > 5).skip(2).take(2));
+    actual.onDone(expectAsync0(() {
+      Expect.listEquals(expected.events, actual.events);
+    }));
+    actual.pause();
+    input.replay(c);
+    actual.resume();
+  });
+}