Add UseCounters for UIEvent.charCode/keyCode/which

Source/core/events/KeyboardEvent.idl

 /*
  * Copyright (C) 2006 Apple Computer, Inc.
  * Copyright (C) 2006 Samuel Weinig <sam.weinig@gmail.com>
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 30 matching lines @@
     void initKeyboardEvent([Default=Undefined] optional DOMString type,
                            [Default=Undefined] optional boolean canBubble,
                            [Default=Undefined] optional boolean cancelable,
                            [Default=Undefined] optional Window view,
                            [Default=Undefined] optional DOMString keyIdentifier,
                            [Default=Undefined] optional unsigned long location,
                            [Default=Undefined] optional boolean ctrlKey,
                            [Default=Undefined] optional boolean altKey,
                            [Default=Undefined] optional boolean shiftKey,
                            [Default=Undefined] optional boolean metaKey);
+
+    readonly attribute long charCode;
+    readonly attribute long keyCode;
+    readonly attribute long which;
 };
-