Make new StreamController be async by default.

tests/standalone/io/string_transformer_test.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.
 
 import "package:expect/expect.dart";
 import "dart:async";
 import "dart:io";
 import "dart:isolate";
 import "dart:utf";
 
 void testUtf8() {
   List<int> data = [0x01,
                     0x7f,
                     0xc2, 0x80,
                     0xdf, 0xbf,
                     0xe0, 0xa0, 0x80,
                     0xef, 0xbf, 0xbf,
                     0xf0, 0x9d, 0x84, 0x9e,
                     0x100, -0x1, -0xFF];
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   controller.add(data);
   controller.close();
   var stringStream = controller.stream
     .transform(new StringDecoder(Encoding.UTF_8));
   stringStream.listen(
     (s) {
       Expect.equals(11, s.length);
       Expect.equals(new String.fromCharCodes([0x01]), s[0]);
       Expect.equals(new String.fromCharCodes([0x7f]), s[1]);
       Expect.equals(new String.fromCharCodes([0x80]), s[2]);
@@ skipping 14 matching lines @@
     });
 }
 
 void testLatin1() {
   List<int> data = [0x01,
                     0x7f,
                     0x44, 0x61, 0x72, 0x74,
                     0x80,
                     0xff,
                     0x100, -0x1, -0xff];
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   controller.add(data);
   controller.close();
   var stream = controller.stream
     .transform(new StringDecoder(Encoding.ISO_8859_1));
   stream.listen((s) {
     Expect.equals(11, s.length);
     Expect.equals(new String.fromCharCodes([0x01]), s[0]);
     Expect.equals(new String.fromCharCodes([0x7f]), s[1]);
     Expect.equals("Dart", s.substring(2, 6));
     Expect.equals(new String.fromCharCodes([0x80]), s[6]);
     Expect.equals(new String.fromCharCodes([0xff]), s[7]);
     Expect.equals('???', s.substring(8, 11));
   });
 }
 
 void testAscii() {
   List<int> data = [0x01,
                     0x44, 0x61, 0x72, 0x74,
                     0x7f,
                     0xf4, 0x100, -0x1, -0xff];
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   controller.add(data);
   controller.close();
   var stream = controller.stream
     .transform(new StringDecoder(Encoding.ASCII));
   stream.listen((s) {
     Expect.equals(10, s.length);
     Expect.equals(new String.fromCharCodes([0x01]), s[0]);
     Expect.equals("Dart", s.substring(1, 5));
     Expect.equals(new String.fromCharCodes([0x7f]), s[5]);
     Expect.equals('????', s.substring(6, 10));
   });
 }
 
 void testReadLine1() {
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   var stream = controller.stream
       .transform(new StringDecoder())
       .transform(new LineTransformer());
 
   var stage = 0;
 
   void stringData(line) {
     var line;
     if (stage == 0) {
       Expect.equals(null, line);
@@ skipping 10 matching lines @@
   }
 
   stream.listen(
       stringData,
       onDone: streamClosed);
 
   controller.add("Line".codeUnits);
 }
 
 void testReadLine2() {
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
 
   var stream = controller.stream
     .transform(new StringDecoder())
     .transform(new LineTransformer());
 
   var stage = 0;
   var subStage = 0;
   stream.listen((line) {
       if (stage == 0) {
         if (subStage == 0) {
@@ skipping 47 matching lines @@
     });
 
   controller.add("Line1\nLine2\r\nLine3\rLi".codeUnits);
 }
 
 class TestException implements Exception {
   TestException();
 }
 
 testErrorHandler() {
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   var errors = 0;
   var stream = controller.stream
     .transform(new StringDecoder())
     .transform(new LineTransformer());
   stream.listen(
       (_) {},
       onDone: () {
         Expect.equals(1, errors);
       },
       onError: (error) {
         errors++;
         Expect.isTrue(error is TestException);
       });
   controller.addError(new TestException());
   controller.close();
 }
 
 testLatin1EncoderError() {
   List<int> data = [0x01,
                     0x7f,
                     0x44, 0x61, 0x72, 0x74,
                     0x80,
                     0xff,
                     0x100];
-  var controller = new StreamController();
+  var controller = new StreamController(sync: true);
   controller.add(new String.fromCharCodes(data));
   controller.close();
   var stream = controller.stream
     .transform(new StringEncoder(Encoding.ISO_8859_1));
   stream.listen(
     (s) {
       Expect.fail("data not expected");
     },
     onError: (error) {
       Expect.isTrue(error is FormatException);
     });
 
 }
 
 main() {
   testUtf8();
   testLatin1();
   testAscii();
   testReadLine1();
   testReadLine2();
   testErrorHandler();
   testLatin1EncoderError();
 }