Mark VoidCallback as a [Callback]

client/dom/frog_dom.dart

 // Copyright (c) 2011, 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.
 
 #library("dom");
 #native("frog_dom.js");
 
@@ skipping 441 matching lines @@
 #source('generated/src/frog/TimeRanges.dart');
 #source('generated/src/frog/Touch.dart');
 #source('generated/src/frog/TouchEvent.dart');
 #source('generated/src/frog/TouchList.dart');
 #source('generated/src/frog/TreeWalker.dart');
 #source('generated/src/frog/UIEvent.dart');
 #source('generated/src/frog/Uint16Array.dart');
 #source('generated/src/frog/Uint32Array.dart');
 #source('generated/src/frog/Uint8Array.dart');
 #source('generated/src/frog/ValidityState.dart');
-#source('generated/src/frog/VoidCallback.dart');
 #source('generated/src/frog/WaveShaperNode.dart');
 #source('generated/src/frog/WebGLActiveInfo.dart');
 #source('generated/src/frog/WebGLBuffer.dart');
 #source('generated/src/frog/WebGLContextAttributes.dart');
 #source('generated/src/frog/WebGLContextEvent.dart');
 #source('generated/src/frog/WebGLDebugRendererInfo.dart');
 #source('generated/src/frog/WebGLDebugShaders.dart');
 #source('generated/src/frog/WebGLFramebuffer.dart');
 #source('generated/src/frog/WebGLProgram.dart');
 #source('generated/src/frog/WebGLRenderbuffer.dart');
@@ skipping 47 matching lines @@
 #source('generated/src/interface/PositionErrorCallback.dart');
 #source('generated/src/interface/SQLStatementCallback.dart');
 #source('generated/src/interface/SQLStatementErrorCallback.dart');
 #source('generated/src/interface/SQLTransactionCallback.dart');
 #source('generated/src/interface/SQLTransactionErrorCallback.dart');
 #source('generated/src/interface/SQLTransactionSyncCallback.dart');
 #source('generated/src/interface/StorageInfoErrorCallback.dart');
 #source('generated/src/interface/StorageInfoQuotaCallback.dart');
 #source('generated/src/interface/StorageInfoUsageCallback.dart');
 #source('generated/src/interface/StringCallback.dart');
+#source('generated/src/interface/VoidCallback.dart');
 
 #source('src/EventListener.dart');
 #source('src/KeyLocation.dart');
 #source('src/KeyName.dart');
 #source('src/RequestAnimationFrameCallback.dart');
 #source('src/TimeoutHandler.dart');
 #source('src/_Collections.dart');
 // #source('src/_FactoryProviders.dart');
 #source('src/_ListIterators.dart');
 #source('src/_Lists.dart');
 
 // TODO(jmesserly): 'native' here is aWork-around for Frog bug.  Frog needs to
 // be smarter about inheriting from a hidden native type (in this case
 // DOMWindow)
 class Window extends DOMWindow native "*Window" {}
 DOMWindow get window() native "return window;";
 // TODO(vsm): Revert to Dart method when 508 is fixed.
 HTMLDocument get document() native "return window.document;";