Omit '= null' as default value in generated dart:html code.

lib/dom/dom.dart

 #library('dom');
 
 // 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.
 
 // DO NOT EDIT
 // Auto-generated Dart DOM library with no implementation.
 
 
 
 // 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.
 
 class _BlobFactoryProvider {
-  factory Blob(List blobParts, [String type = null, String endings = null]) => _dummy();
+  factory Blob(List blobParts, [String type, String endings]) => _dummy();
 }
 // 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.
 
 class _DOMParserFactoryProvider {
   factory DOMParser() => _dummy();
 }
 // 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.
 
 class _DOMURLFactoryProvider {
   factory DOMURL() => _dummy();
 }
 // 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.
 
 class _DataViewFactoryProvider {
-  factory DataView(ArrayBuffer buffer, [int byteOffset = null, int byteLength = null]) => _dummy();
+  factory DataView(ArrayBuffer buffer, [int byteOffset, int byteLength]) => _dummy();
 }
 // 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.
 
 class _DeprecatedPeerConnectionFactoryProvider {
   factory DeprecatedPeerConnection(String serverConfiguration, SignalingCallback signalingCallback) => _dummy();
 }
 // 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 14 matching lines @@
 // BSD-style license that can be found in the LICENSE file.
 
 class _FileReaderSyncFactoryProvider {
   factory FileReaderSync() => _dummy();
 }
 // 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.
 
 class _HTMLAudioElementFactoryProvider {
-  factory HTMLAudioElement([String src = null]) => _dummy();
+  factory HTMLAudioElement([String src]) => _dummy();
 }
 // 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.
 
 class _HTMLOptionElementFactoryProvider {
-  factory HTMLOptionElement([String data = null, String value = null, bool defaultSelected = null, bool selected = null]) => _dummy();
+  factory HTMLOptionElement([String data, String value, bool defaultSelected, bool selected]) => _dummy();
 }
 // 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.
 
 class _IceCandidateFactoryProvider {
   factory IceCandidate(String label, String candidateLine) => _dummy();
 }
 // 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 14 matching lines @@
 // BSD-style license that can be found in the LICENSE file.
 
 class _MessageChannelFactoryProvider {
   factory MessageChannel() => _dummy();
 }
 // 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.
 
 class _NotificationFactoryProvider {
-  factory Notification(String title, [Map options = null]) => _dummy();
+  factory Notification(String title, [Map options]) => _dummy();
 }
 // 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.
 
 class _PeerConnection00FactoryProvider {
   factory PeerConnection00(String serverConfiguration, IceCallback iceCallback) => _dummy();
 }
 // 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.
 
 class _SessionDescriptionFactoryProvider {
   factory SessionDescription(String sdp) => _dummy();
 }
 // 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.
 
 class _ShadowRootFactoryProvider {
   factory ShadowRoot(Element host) => _dummy();
 }
 // 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.
 
 class _SharedWorkerFactoryProvider {
-  factory SharedWorker(String scriptURL, [String name = null]) => _dummy();
+  factory SharedWorker(String scriptURL, [String name]) => _dummy();
 }
 // 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.
 
 class _SpeechGrammarFactoryProvider {
   factory SpeechGrammar() => _dummy();
 }
 // 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.
 
 class _SpeechGrammarListFactoryProvider {
   factory SpeechGrammarList() => _dummy();
 }
 // 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.
 
 class _SpeechRecognitionFactoryProvider {
   factory SpeechRecognition() => _dummy();
 }
 // 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.
 
 class _TextTrackCueFactoryProvider {
-  factory TextTrackCue(String id, num startTime, num endTime, String text, [String settings = null, bool pauseOnExit = null]) => _dummy();
+  factory TextTrackCue(String id, num startTime, num endTime, String text, [String settings, bool pauseOnExit]) => _dummy();
 }
 // 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.
 
 class _WebKitCSSMatrixFactoryProvider {
-  factory WebKitCSSMatrix([String cssValue = null]) => _dummy();
+  factory WebKitCSSMatrix([String cssValue]) => _dummy();
 }
 // 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.
 
 class _WorkerFactoryProvider {
   factory Worker(String scriptUrl) => _dummy();
 }
 // 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 12767 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.
 
 Window get window() => _dummy();
 
 // TODO(vsm): Remove when prefixes are supported.
 Window get dom_window() => _dummy();
 
 Document get document() => _dummy();