Fixing IndexedDB's deleteDatabase to have the correct future result.

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 386 matching lines @@
 
   @DomName('IDBFactory.deleteDatabase')
   Future<IdbFactory> deleteDatabase(String name,
       {void onBlocked(Event)}) {
     try {
       var request = $dom_deleteDatabase(name);
 
       if (onBlocked != null) {
         request.onBlocked.listen(onBlocked);
       }
-      return _completeRequest(request);
+      var completer = new Completer.sync();
+      request.onSuccess.listen((e) {
+        completer.complete(this);
+      });
+      request.onError.listen((e) {
+        completer.completeError(e);
+      });
+      return completer.future;
     } catch (e, stacktrace) {
       return new Future.error(e, stacktrace);
     }
   }
 
   @DomName('IDBFactory.getDatabaseNames')
   @SupportedBrowser(SupportedBrowser.CHROME)
   @Experimental
   Future<List<String>> getDatabaseNames() {
     try {
@@ skipping 833 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" {
 }