Make new StreamController be async by default.

tests/lib/async/stream_state_test.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.
 
 // Test the event/callback protocol of the stream implementations.
 library stream_state_test;
 
 import "../../../pkg/unittest/lib/unittest.dart";
 import "stream_state_helper.dart";
 
 const ms5 = const Duration(milliseconds: 5);
 
 main() {
   mainTest(false);
   // TODO(floitsch): reenable?
   // mainTest(true);
 }
 
 mainTest(bool broadcast) {
   var p = broadcast ? "BC" : "SC";
   test("$p-sub-data-done", () {
-    var t = new StreamProtocolTest(broadcast);
-    t..expectSubscription()
+    var t = new StreamProtocolTest(broadcast: broadcast);
+    t..expectListen()
      ..expectData(42)
      ..expectDone()
      ..expectCancel();
-    t..subscribe()..add(42)..close();
+    t..listen()..add(42)..close();
   });
 
   test("$p-data-done-sub", () {
-    var t = new StreamProtocolTest(broadcast);
+    var t = new StreamProtocolTest(broadcast: broadcast);
     if (broadcast) {
       t..expectDone();
     } else {
-      t..expectSubscription()
+      t..expectListen()
        ..expectData(42)
        ..expectDone()
        ..expectCancel();
     }
-    t..add(42)..close()..subscribe();
+    t..add(42)..close()..listen();
   });
 
   test("$p-sub-data/pause+resume-done", () {
-    var t = new StreamProtocolTest(broadcast);
-    t..expectSubscription()
+    var t = new StreamProtocolTest(broadcast: broadcast);
+    t..expectListen()
      ..expectData(42, () {
          t.pause();
          t.resume();
          t.close();
        })
      ..expectDone()
      ..expectCancel();
-    t..subscribe()..add(42);
+    t..listen()..add(42);
   });
 
   test("$p-sub-data-unsubonerror", () {
-    var t = new StreamProtocolTest(broadcast);
-    t..expectSubscription()
+    var t = new StreamProtocolTest(broadcast: broadcast);
+    t..expectListen()
      ..expectData(42)
      ..expectError("bad")
      ..expectCancel();
-    t..subscribe(cancelOnError: true)
+    t..listen(cancelOnError: true)
      ..add(42)
      ..error("bad")
      ..add(43)
      ..close();
   });
 
   test("$p-sub-data-no-unsubonerror", () {
-    var t = new StreamProtocolTest(broadcast);
-    t..expectSubscription()
+    var t = new StreamProtocolTest(broadcast: broadcast);
+    t..expectListen()
      ..expectData(42)
      ..expectError("bad")
      ..expectData(43)
      ..expectDone()
      ..expectCancel();
-    t..subscribe(cancelOnError: false)
+    t..listen(cancelOnError: false)
      ..add(42)
      ..error("bad")
      ..add(43)
      ..close();
   });
 
   test("$p-pause-resume-during-event", () {
-    var t = new StreamProtocolTest(broadcast);
-    t..expectSubscription()
+    var t = new StreamProtocolTest(broadcast: broadcast);
+    t..expectListen()
      ..expectData(42, () {
        t.pause();
        t.resume();
      })
      ..expectDone()
      ..expectCancel();
-    t..subscribe()
+    t..listen()
      ..add(42)
      ..close();
   });
 }