Use viewportConstrainedVisibleContentRect() to get the scrolling offset

Source/core/rendering/RenderLayerClipper.cpp

Index: Source/core/rendering/RenderLayerClipper.cpp
diff --git a/Source/core/rendering/RenderLayerClipper.cpp b/Source/core/rendering/RenderLayerClipper.cpp
index 4f5e3850463b3034fd6b20dbec8b08d3b33e4370..3427347d8493bb77bce9ce85d5f90bd10b4bd2fe 100644
--- a/Source/core/rendering/RenderLayerClipper.cpp
+++ b/Source/core/rendering/RenderLayerClipper.cpp
@@ -73,7 +73,7 @@ static void applyClipRects(const ClipRectsContext& context, RenderObject& render
     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);
@@ -335,7 +335,7 @@ ClipRect RenderLayerClipper::backgroundClipRect(const ClipRectsContext& context)
 
     // 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;
 }