Add constructors to all the event classes.

client/html/src/EventWrappingImplementation.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 EventWrappingImplementation extends DOMWrapperBase implements Event {
   EventWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
 
+  factory EventWrappingImplementation(String type, [bool canBubble = false,
+      bool cancelable = false]) {
+    var e = dom.document.createEvent("Event");
+    e.initEvent(type, canBubble, cancelable);
+    return LevelDom.wrapEvent(e);
+  }
+
   bool get bubbles() { return _ptr.bubbles; }
 
   bool get cancelBubble() { return _ptr.cancelBubble; }
 
   void set cancelBubble(bool value) { _ptr.cancelBubble = value; }
 
   bool get cancelable() { return _ptr.cancelable; }
 
   EventTarget get currentTarget() { return LevelDom.wrapEventTarget(_ptr.currentTarget); }
 
   bool get defaultPrevented() { return _ptr.defaultPrevented; }
 
   int get eventPhase() { return _ptr.eventPhase; }
 
   bool get returnValue() { return _ptr.returnValue; }
 
   void set returnValue(bool value) { _ptr.returnValue = value; }
 
   EventTarget get srcElement() { return LevelDom.wrapEventTarget(_ptr.srcElement); }
 
   EventTarget get target() { return LevelDom.wrapEventTarget(_ptr.target); }
 
   int get timeStamp() { return _ptr.timeStamp; }
 
   String get type() { return _ptr.type; }
 
-  void initEvent(String eventTypeArg, bool canBubbleArg, bool cancelableArg) {
-    _ptr.initEvent(eventTypeArg, canBubbleArg, cancelableArg);
-    return;
-  }
-
   void preventDefault() {
     _ptr.preventDefault();
     return;
   }
 
   void stopImmediatePropagation() {
     _ptr.stopImmediatePropagation();
     return;
   }
 
   void stopPropagation() {
     _ptr.stopPropagation();
     return;
   }
 }