Make elementFromPoint() arguments non-optional

Source/core/dom/Document.idl

 /*
  * Copyright (C) 2006, 2007, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2006, 2007 Samuel Weinig <sam@webkit.org>
  *
  * 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 114 matching lines @@
 
     [PerWorldBindings] NodeList getElementsByName(DOMString elementName);
 
     [PutForwards=href] readonly attribute Location location;
 
     // IE extensions
     [MeasureAs=DocumentCharset, TreatReturnedNullStringAs=Undefined, TreatNullAs=NullString] attribute DOMString charset;
     [MeasureAs=DocumentDefaultCharset, TreatReturnedNullStringAs=Undefined] readonly attribute DOMString defaultCharset;
     [TreatReturnedNullStringAs=Undefined] readonly attribute DOMString readyState;
 
-    Element            elementFromPoint([Default=Undefined] optional long x,
-                                        [Default=Undefined] optional long y);
+    Element            elementFromPoint(long x, long y);
     [MeasureAs=DocumentCaretRangeFromPoint]
     Range              caretRangeFromPoint([Default=Undefined] optional long x,
                                            [Default=Undefined] optional long y);
 
     // Mozilla extensions
     Selection          getSelection();
     readonly attribute DOMString? characterSet;
 
     // WebKit extensions
 
@@ skipping 57 matching lines @@
     // TODO(davidben): This is a property so attaching a deprecation warning results in false positives when outputting
     // document in the console. It's possible http://crbug.com/43394 will resolve this.
     [MeasureAs=PrefixedPageVisibility, ImplementedAs=visibilityState] readonly attribute DOMString webkitVisibilityState;
     [MeasureAs=PrefixedPageVisibility, ImplementedAs=hidden] readonly attribute boolean webkitHidden;
 
     readonly attribute HTMLScriptElement currentScript;
 };
 
 Document implements GlobalEventHandlers;
 Document implements ParentNode;