Use viewportConstrainedVisibleContentRect() to get the scrolling offset

Source/core/rendering/RenderLayerClipper.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2009, 2010, 2011, 2012 Apple Inc. All rights reserved.
  *
  * Portions are Copyright (C) 1998 Netscape Communications Corporation.
  *
  * Other contributors:
  *   Robert O'Callahan <roc+@cs.cmu.edu>
  *   David Baron <dbaron@fas.harvard.edu>
  *   Christian Biesinger <cbiesinger@web.de>
  *   Randall Jesup <rjesup@wgate.com>
@@ skipping 55 matching lines @@
     }
 }
 
 static void applyClipRects(const ClipRectsContext& context, RenderObject& renderer, LayoutPoint offset, ClipRects& clipRects)
 {
     ASSERT(renderer.hasOverflowClip() || renderer.hasClip());
 
     RenderView* view = renderer.view();
     ASSERT(view);
     if (clipRects.fixed() && context.rootLayer->renderer() == view)
-        offset -= view->frameView()->scrollOffsetForFixedPosition();
+        offset -= view->frameView()->scrollOffsetForViewportConstrainedObjects();
 
     if (renderer.hasOverflowClip()) {
         ClipRect newOverflowClip = toRenderBox(renderer).overflowClipRect(offset, context.scrollbarRelevancy);
         newOverflowClip.setHasRadius(renderer.style()->hasBorderRadius());
         clipRects.setOverflowClipRect(intersection(newOverflowClip, clipRects.overflowClipRect()));
         if (renderer.isPositioned())
             clipRects.setPosClipRect(intersection(newOverflowClip, clipRects.posClipRect()));
     }
 
     if (renderer.hasClip()) {
@@ skipping 241 matching lines @@
     RefPtr<ClipRects> parentClipRects = ClipRects::create();
     if (m_renderer.layer() == context.rootLayer)
         parentClipRects->reset(LayoutRect::infiniteIntRect());
     else
         m_renderer.layer()->parent()->clipper().getOrCalculateClipRects(context, *parentClipRects);
 
     ClipRect result = backgroundClipRectForPosition(*parentClipRects, m_renderer.style()->position());
 
     // Note: infinite clipRects should not be scrolled here, otherwise they will accidentally no longer be considered infinite.
     if (parentClipRects->fixed() && context.rootLayer->renderer() == m_renderer.view() && result != LayoutRect::infiniteIntRect())
-        result.move(m_renderer.view()->frameView()->scrollOffsetForFixedPosition());
+        result.move(m_renderer.view()->frameView()->scrollOffsetForViewportConstrainedObjects());
 
     return result;
 }
 
 void RenderLayerClipper::getOrCalculateClipRects(const ClipRectsContext& context, ClipRects& clipRects) const
 {
     if (context.usesCache())
         clipRects = *getClipRects(context);
     else
         calculateClipRects(context, clipRects);
@@ skipping 17 matching lines @@
         ASSERT(current);
         if (current->transform() || current->isPaintInvalidationContainer())
             return const_cast<RenderLayer*>(current);
     }
 
     ASSERT_NOT_REACHED();
     return 0;
 }
 
 } // namespace blink