Add support for DOM Level 3 WheelEvent

Source/core/page/Window.idl

 /*
  * Copyright (C) 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2011 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 190 matching lines @@
     attribute EventHandler onloadedmetadata;
     attribute EventHandler onloadstart;
     attribute EventHandler onmessage;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmousedown;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmouseenter;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmouseleave;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmousemove;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmouseout;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmouseover;
     [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmouseup;
-    [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmousewheel;
+    [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onmousewheel; // Deprecated in favor of onwheel.
+    [PerWorldBindings, ActivityLog=SetterForIsolatedWorlds] attribute EventHandler onwheel;
     attribute EventHandler onoffline;
     attribute EventHandler ononline;
     attribute EventHandler onpagehide;
     attribute EventHandler onpageshow;
     attribute EventHandler onpause;
     attribute EventHandler onplay;
     attribute EventHandler onplaying;
     attribute EventHandler onpopstate;
     attribute EventHandler onprogress;
     attribute EventHandler onratechange;
@@ skipping 79 matching lines @@
     // window.toString() requires special handling in V8
     [DoNotCheckSignature, DoNotCheckSecurity, Custom, NotEnumerable] DOMString toString();
 
     [ImplementedAs=anonymousIndexedGetter, NotEnumerable] getter Window(unsigned long index);
     [Custom, NotEnumerable] getter Window (DOMString name);
 };
 
 Window implements ImageBitmapFactories;
 Window implements WindowTimers;
 Window implements WindowBase64;