Add constructors to all the event classes.

client/html/src/EventWrappingImplementation.dart

Index: client/html/src/EventWrappingImplementation.dart
diff --git a/client/html/generated/src/wrapping/_EventWrappingImplementation.dart b/client/html/src/EventWrappingImplementation.dart
similarity index 85%
rename from client/html/generated/src/wrapping/_EventWrappingImplementation.dart
rename to client/html/src/EventWrappingImplementation.dart
index 0e6d27f25101a831b4a916be5f91195557990d8a..cb71171064339480222511187e7534e13babaf13 100644
--- a/client/html/generated/src/wrapping/_EventWrappingImplementation.dart
+++ b/client/html/src/EventWrappingImplementation.dart
@@ -2,11 +2,16 @@
 // 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; }
@@ -33,11 +38,6 @@ class EventWrappingImplementation extends DOMWrapperBase implements Event {
 
   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;