Add constructors to all the event classes.

client/html/generated/src/wrapping/_WheelEventWrappingImplementation.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 WheelEventWrappingImplementation extends UIEventWrappingImplementation implements WheelEvent {
-  WheelEventWrappingImplementation._wrap(ptr) : super._wrap(ptr) {}
-
-  bool get altKey() { return _ptr.altKey; }
-
-  int get clientX() { return _ptr.clientX; }
-
-  int get clientY() { return _ptr.clientY; }
-
-  bool get ctrlKey() { return _ptr.ctrlKey; }
-
-  bool get metaKey() { return _ptr.metaKey; }
-
-  int get offsetX() { return _ptr.offsetX; }
-
-  int get offsetY() { return _ptr.offsetY; }
-
-  int get screenX() { return _ptr.screenX; }
-
-  int get screenY() { return _ptr.screenY; }
-
-  bool get shiftKey() { return _ptr.shiftKey; }
-
-  int get wheelDelta() { return _ptr.wheelDelta; }
-
-  int get wheelDeltaX() { return _ptr.wheelDeltaX; }
-
-  int get wheelDeltaY() { return _ptr.wheelDeltaY; }
-
-  int get x() { return _ptr.x; }
-
-  int get y() { return _ptr.y; }
-
-  void initWheelEvent(int wheelDeltaX, int wheelDeltaY, Window view, int screenX, int screenY, int clientX, int clientY, bool ctrlKey, bool altKey, bool shiftKey, bool metaKey) {
-    _ptr.initWheelEvent(wheelDeltaX, wheelDeltaY, LevelDom.unwrap(view), screenX, screenY, clientX, clientY, ctrlKey, altKey, shiftKey, metaKey);
-    return;
-  }
-}