Merge request - fixes dart2js async problems.

tests/language/asyncstar_throw_in_catch_test.dart

+// Copyright (c) 2015, 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.
+
+import "dart:async";
+import "package:expect/expect.dart";
+import "package:async_helper/async_helper.dart";
+
+class Tracer {
+  final String expected;
+  final String name;
+  int counter = 0;
+
+  Tracer(this.expected, [this.name]);
+
+  void trace(msg) {
+    if (name != null) {
+      print("Tracing $name: $msg");
+    }
+    Expect.equals(expected[counter], msg);
+    counter++;
+  }
+
+  void done() {
+    Expect.equals(expected.length, counter, "Received too few traces");
+  }
+}
+
+foo1(Tracer tracer) async* {
+  try {
+    tracer.trace("a");
+    await new Future.value(3);
+    tracer.trace("b");
+    throw "Error";
+  } catch (e) {
+    tracer.trace("c");
+    yield 1;
+    tracer.trace("d");
+    yield 2;
+    tracer.trace("e");
+    await new Future.error("Error2");
+  } finally {
+    tracer.trace("f");
+  }
+  tracer.trace("g");
+}
+
+test() async {
+  Tracer tracer;
+
+  Completer foo1Done = new Completer();
+  tracer = new Tracer("abcdf");
+  var subscription;
+  subscription = foo1(tracer).listen((event) async {
+    await subscription.cancel();
+    tracer.done();
+    foo1Done.complete(null);
+  });
+  await foo1Done.future;
+}
+
+
+void main() {
+  asyncTest(test);
+}