Update Element API for CSSOM smooth scrolling to match the spec

Source/core/dom/Element.idl

 /*
  * Copyright (C) 2006, 2007, 2009 Apple Inc. All rights reserved.
  * 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 51 matching lines @@
     readonly attribute long offsetLeft;
     readonly attribute long offsetTop;
     readonly attribute long offsetWidth;
     readonly attribute long offsetHeight;
     [ImplementedAs=offsetParentForBindings, PerWorldBindings] readonly attribute Element offsetParent;
     readonly attribute long clientLeft;
     readonly attribute long clientTop;
     readonly attribute long clientWidth;
     readonly attribute long clientHeight;
 
-    // FIXME: should be:
-    // attribute (Dictionary or double) scrollLeft;
-    // attribute (Dictionary or double) scrollTop;
-    // http://crbug.com/240176
-    [Custom=Setter] attribute double scrollLeft;
-    [Custom=Setter] attribute double scrollTop;
+    attribute double scrollLeft;
+    attribute double scrollTop;
     readonly attribute long scrollWidth;
     readonly attribute long scrollHeight;
 
+    [RuntimeEnabled=CSSOMSmoothScroll] void scroll(double x, double y);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scroll(optional ScrollToOptions scrollToOptions);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollTo(double x, double y);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollTo(optional ScrollToOptions scrollToOptions);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollBy(double x, double y);
+    [RuntimeEnabled=CSSOMSmoothScroll] void scrollBy(optional ScrollToOptions scrollToOptions);
+
     void focus();
     void blur();
     void scrollIntoView(optional boolean alignWithTop);
 
     // WebKit extensions
 
     [MeasureAs=ElementScrollIntoViewIfNeeded] void scrollIntoViewIfNeeded(optional boolean centerIfNeeded);
 
     // HTML 5
     HTMLCollection getElementsByClassName(DOMString classNames);
@@ skipping 34 matching lines @@
     attribute EventHandler onselectstart;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchcancel;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchend;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchmove;
     [RuntimeEnabled=Touch] attribute EventHandler ontouchstart;
     attribute EventHandler onwheel;
 };
 
 Element implements ParentNode;
 Element implements ChildNode;