Safely wrap window.top in frog dom.

client/dom/generated/src/wrapping/_FileEntryWrappingImplementation.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.
 
 // WARNING: Do not edit - generated code.
 
 class _FileEntryWrappingImplementation extends _EntryWrappingImplementation implements FileEntry {
   _FileEntryWrappingImplementation() : super() {}
 
   static create__FileEntryWrappingImplementation() native {
     return new _FileEntryWrappingImplementation();
   }
 
   void createWriter(FileWriterCallback successCallback, [ErrorCallback errorCallback = null]) {
-    if (errorCallback === null) {
-      _createWriter(this, successCallback);
-      return;
-    } else {
-      _createWriter_2(this, successCallback, errorCallback);
-      return;
-    }
+    _createWriter(this, successCallback, errorCallback);
+    return;
   }
-  static void _createWriter(receiver, successCallback) native;
-  static void _createWriter_2(receiver, successCallback, errorCallback) native;
+  static void _createWriter(receiver, successCallback, errorCallback) native;
 
   void file(FileCallback successCallback, [ErrorCallback errorCallback = null]) {
-    if (errorCallback === null) {
-      _file(this, successCallback);
-      return;
-    } else {
-      _file_2(this, successCallback, errorCallback);
-      return;
-    }
+    _file(this, successCallback, errorCallback);
+    return;
   }
-  static void _file(receiver, successCallback) native;
-  static void _file_2(receiver, successCallback, errorCallback) native;
+  static void _file(receiver, successCallback, errorCallback) native;
 
   String get typeName() { return "FileEntry"; }
 }