Add constructors to all the event classes.

client/html/src/UIEventWrappingImplementation.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 UIEventWrappingImplementation extends EventWrappingImplementation implements UIEvent {
   UIEventWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
+  factory UIEventWrappingImplementation(String type, Window view, int detail,
+      [bool canBubble = false, bool cancelable = false]) {
+    var e = dom.document.createEvent("UIEvent");
+    e.initUIEvent(type, canBubble, cancelable, LevelDom.unwrap(view), detail);
+    return LevelDom.wrapUIEvent(e);
+  }
+
   int get charCode() { return _ptr.charCode; }
 
   int get detail() { return _ptr.detail; }
 
   int get keyCode() { return _ptr.keyCode; }
 
   int get layerX() { return _ptr.layerX; }
 
   int get layerY() { return _ptr.layerY; }
 
   int get pageX() { return _ptr.pageX; }
 
   int get pageY() { return _ptr.pageY; }
 
   Window get view() { return LevelDom.wrapWindow(_ptr.view); }
 
   int get which() { return _ptr.which; }
-
-  void initUIEvent(String type, bool canBubble, bool cancelable, Window view, int detail) {
-    _ptr.initUIEvent(type, canBubble, cancelable, LevelDom.unwrap(view), detail);
-    return;
-  }
 }