Fix layoutOverflowRect in case of explicit 'overflow: scroll', but no overflow content

Source/core/rendering/RenderBox.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Adobe Systems Incorporated. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 4265 matching lines @@
     m_overflow->addVisualOverflow(rect);
 }
 
 void RenderBox::addContentsVisualOverflow(const LayoutRect& rect)
 {
     if (!hasOverflowClip()) {
         addVisualOverflow(rect);
         return;
     }
 
-    if (!m_overflow) {
-        LayoutRect clientBox = clientBoxRect();
-        if (style()->shouldPlaceBlockDirectionScrollbarOnLogicalLeft())
-            clientBox.move(-verticalScrollbarWidth(), 0);
-        m_overflow = adoptPtr(new RenderOverflow(clientBox, borderBoxRect()));
-    }
+    if (!m_overflow)
+        m_overflow = adoptPtr(new RenderOverflow(noOverflowRect(), borderBoxRect()));
     m_overflow->addContentsVisualOverflow(rect);
 }
 
 void RenderBox::clearLayoutOverflow()
 {
     if (!m_overflow)
         return;
 
     if (!hasVisualOverflow() && contentsVisualOverflowRect().isEmpty()) {
         m_overflow.clear();
@@ skipping 390 matching lines @@
         return 0;
 
     if (!layoutState && !flowThreadContainingBlock())
         return 0;
 
     RenderBlock* containerBlock = containingBlock();
     return containerBlock->offsetFromLogicalTopOfFirstPage() + logicalTop();
 }
 
 } // namespace WebCore