document.documentElement.scrollTop/Left is zero

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 668 matching lines @@
     }
 
     if (RenderBox* renderer = renderBox())
         return adjustLayoutUnitForAbsoluteZoom(renderer->pixelSnappedClientHeight(), renderer).round();
     return 0;
 }
 
 int Element::scrollLeft()
 {
     document().updateLayoutIgnorePendingStylesheets();
+
+    if (document().documentElement() == this) {
+        if (document().inQuirksMode())
+            return 0;
+
+        if (FrameView* view = document().view()) {
+            if (RenderView* renderView = document().renderView())
+                return adjustForAbsoluteZoom(view->scrollX(), renderView);
+        }
+    }
+
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollLeft(), rend);
     return 0;
 }
 
 int Element::scrollTop()
 {
     document().updateLayoutIgnorePendingStylesheets();
+
+    if (document().documentElement() == this) {
+        if (document().inQuirksMode())
+            return 0;
+
+        if (FrameView* view = document().view()) {
+            if (RenderView* renderView = document().renderView())
+                return adjustForAbsoluteZoom(view->scrollY(), renderView);
+        }
+    }
+
     if (RenderBox* rend = renderBox())
         return adjustForAbsoluteZoom(rend->scrollTop(), rend);
     return 0;
 }
 
 void Element::setScrollLeft(int newLeft)
 {
     document().updateLayoutIgnorePendingStylesheets();
     if (RenderBox* rend = renderBox())
         rend->setScrollLeft(static_cast<int>(newLeft * rend->style()->effectiveZoom()));
@@ skipping 2967 matching lines @@
     return 0;
 }
 
 Attribute* UniqueElementData::attributeItem(unsigned index)
 {
     ASSERT_WITH_SECURITY_IMPLICATION(index < length());
     return &m_attributeVector.at(index);
 }
 
 } // namespace WebCore