Add constructors to all the event classes.

client/html/src/CloseEventWrappingImplementation.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 CloseEventWrappingImplementation extends EventWrappingImplementation implements CloseEvent {
   CloseEventWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
+  factory CloseEventWrappingImplementation(String type, int code, String reason,
+      [bool canBubble = false, bool cancelable = false, bool wasClean = true]) {
+    var e = dom.document.createEvent("CloseEvent");
+    e.initCloseEvent(type, canBubble, cancelable, wasClean, code, reason);
+    return LevelDom.wrapCloseEvent(e);
+  }
+
   int get code() { return _ptr.code; }
 
   String get reason() { return _ptr.reason; }
 
   bool get wasClean() { return _ptr.wasClean; }
-
-  void initCloseEvent(String typeArg, bool canBubbleArg, bool cancelableArg, bool wasCleanArg, int codeArg, String reasonArg) {
-    _ptr.initCloseEvent(typeArg, canBubbleArg, cancelableArg, wasCleanArg, codeArg, reasonArg);
-    return;
-  }
 }