Non-composited scrolling div should invalidate when it has descendant paints to its backing

Source/core/rendering/RenderLayerScrollableArea.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 370 matching lines @@
     frame->eventHandler().dispatchFakeMouseMoveEventSoonInQuad(quadForFakeMouseMoveEvent);
 
     bool requiresRepaint = true;
 
     if (!box().isMarquee() && box().view()->compositor()->inCompositingMode()) {
         // Hits in virtual/gpu/fast/canvas/canvas-scroll-path-into-view.html.
         DisableCompositingQueryAsserts disabler;
         bool onlyScrolledCompositedLayers = scrollsOverflow()
             && !layer()->hasVisibleNonLayerContent()
             && !layer()->hasNonCompositedChild()
-            && !layer()->hasBlockSelectionGapBounds();
+            && !layer()->hasBlockSelectionGapBounds()
+            && box().style()->backgroundLayers().attachment() != LocalBackgroundAttachment;
 
         if (usesCompositedScrolling() || onlyScrolledCompositedLayers)
             requiresRepaint = false;
     }
 
     // Just schedule a full repaint of our object.
     if (requiresRepaint) {
         if (box().frameView()->isInPerformLayout())
             box().setShouldDoFullPaintInvalidation(true);
         else
@@ skipping 1049 matching lines @@
 void RenderLayerScrollableArea::setTopmostScrollChild(RenderLayer* scrollChild)
 {
     // We only want to track the topmost scroll child for scrollable areas with
     // overlay scrollbars.
     if (!hasOverlayScrollbars())
         return;
     m_nextTopmostScrollChild = scrollChild;
 }
 
 } // namespace blink