Make new StreamController be async by default.

sdk/lib/indexed_db/dart2js/indexed_db_dart2js.dart

 library dart.dom.indexed_db;
 
 import 'dart:async';
 import 'dart:html';
 import 'dart:html_common';
 import 'dart:typed_data';
 import 'dart:_js_helper' show Creates, Returns, JSName, Null;
 import 'dart:_foreign_helper' show JS;
 // 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
@@ skipping 140 matching lines @@
 
   @DomName('IDBCursor.value')
   Future update(value) {
    try {
       return _completeRequest($dom_update(value));
     } catch (e, stacktrace) {
       return new Future.error(e, stacktrace);
     }
   }
 
-  
+
   @DomName('IDBCursor.direction')
   @DocsEditable
   final String direction;
 
   @DomName('IDBCursor.key')
   @DocsEditable
   @_annotation_Creates_IDBKey
   @_annotation_Returns_IDBKey
   final Object key;
 
@@ skipping 406 matching lines @@
     }
     var request;
     if (direction == null) {
       request = $dom_openKeyCursor(key_OR_range);
     } else {
       request = $dom_openKeyCursor(key_OR_range, direction);
     }
     return ObjectStore._cursorStreamFromResult(request, autoAdvance);
   }
 
-  
+
   @DomName('IDBIndex.keyPath')
   @DocsEditable
   final dynamic keyPath;
 
   @DomName('IDBIndex.multiEntry')
   @DocsEditable
   final bool multiEntry;
 
   @DomName('IDBIndex.name')
   @DocsEditable
@@ skipping 410 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 228 matching lines @@
 // 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.
 
 
 @DocsEditable
 @DomName('IDBAny')
 @deprecated // nonstandard
 abstract class _IDBAny native "IDBAny" {
 }