Make new StreamController be async by default.

sdk/lib/indexed_db/dartium/indexed_db_dartium.dart

 library dart.dom.indexed_db;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:nativewrappers';
 // 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.
 
@@ skipping 859 matching lines @@
 
 
   /**
    * Helper for iterating over cursors in a request.
    */
   static Stream<Cursor> _cursorStreamFromResult(Request request,
       bool autoAdvance) {
     // TODO: need to guarantee that the controller provides the values
     // immediately as waiting until the next tick will cause the transaction to
     // close.
-    var controller = new StreamController();
+    var controller = new StreamController(sync: true);
 
     request.onError.listen((e) {
       //TODO: Report stacktrace once issue 4061 is resolved.
       controller.addError(e);
     });
 
     request.onSuccess.listen((e) {
       Cursor cursor = request.result;
       if (cursor == null) {
         controller.close();
@@ skipping 235 matching lines @@
 // WARNING: Do not edit - generated code.
 
 
 @DocsEditable
 @DomName('IDBAny')
 @deprecated // nonstandard
 abstract class _IDBAny extends NativeFieldWrapperClass1 {
   _IDBAny.internal();
 
 }