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

Source/core/rendering/RenderLayer.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 624 matching lines @@
     m_hasVisibleNonLayerContent = false;
     for (RenderObject* r = renderer()->slowFirstChild(); r; r = r->nextSibling()) {
         if (!r->hasLayer()) {
             m_hasVisibleNonLayerContent = true;
             break;
         }
     }
 
     m_hasNonCompositedChild = false;
     for (RenderLayer* child = firstChild(); child; child = child->nextSibling()) {
-        if (child->compositingState() == NotComposited) {
+        if (child->compositingState() == NotComposited || child->compositingState() == HasOwnBackingButPaintsIntoAncestor) {
             m_hasNonCompositedChild = true;
             return;
         }
     }
 }
 
 // The descendant-dependent flags system is badly broken because we clean dirty
 // bits in upward tree walks, which means we need to call updateDescendantDependentFlags
 // at every node in the tree to fully clean all the dirty bits. While we'll in
 // the process of fixing this issue, updateDescendantDependentFlagsForEntireSubtree
@@ skipping 3089 matching lines @@
     }
 }
 
 void showLayerTree(const blink::RenderObject* renderer)
 {
     if (!renderer)
         return;
     showLayerTree(renderer->enclosingLayer());
 }
 #endif