Fix scrollWidth/Height to not truncate scroll offset

Source/core/dom/Element.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Peter Kelly (pmk@post.com)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2012, 2013 Apple Inc. All rights reserved.
  *           (C) 2007 Eric Seidel (eric@webkit.org)
  *
  * This library is free software; you can redistribute it and/or
@@ skipping 786 matching lines @@
     }
 
     // FIXME: Use scrollBehavior to decide whether to scroll smoothly or instantly.
     setScrollTop(position);
 }
 
 double Element::scrollWidth()
 {
     document().updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
-        return adjustForAbsoluteZoom(rend->scrollWidth(), rend);
+        return adjustLayoutUnitForAbsoluteZoom(rend->scrollWidth(), *rend).toDouble();
     return 0;
 }
 
 double Element::scrollHeight()
 {
     document().updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
-        return adjustForAbsoluteZoom(rend->scrollHeight(), rend);
+        return adjustLayoutUnitForAbsoluteZoom(rend->scrollHeight(), *rend).toDouble();
     return 0;
 }
 
 IntRect Element::boundsInRootViewSpace()
 {
     document().updateLayoutIgnorePendingStylesheets();
 
     FrameView* view = document().view();
     if (!view)
         return IntRect();
@@ skipping 2497 matching lines @@
 
 void Element::trace(Visitor* visitor)
 {
     if (hasRareData())
         visitor->trace(elementRareData());
 
     ContainerNode::trace(visitor);
 }
 
 } // namespace WebCore