DeprecatedPaintLayerStackingNode should walk DPL

Source/core/paint/DeprecatedPaintLayer.h

 /*
  * Copyright (C) 2003, 2009, 2012 Apple Inc. All rights reserved.
  * Copyright (C) 2013 Intel Corporation. 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>
@@ skipping 375 matching lines @@
             DeprecatedPaintLayerFilterInfo::removeFilterInfoForLayer(this);
     }
 
     bool hasFilterInfo() const { return m_hasFilterInfo; }
     void setHasFilterInfo(bool hasFilterInfo) { m_hasFilterInfo = hasFilterInfo; }
 
     void updateFilters(const ComputedStyle* oldStyle, const ComputedStyle& newStyle);
 
     Node* enclosingElement() const;
 
+    bool isInTopLayer() const;
+
     bool scrollsWithViewport() const;
     bool scrollsWithRespectTo(const DeprecatedPaintLayer*) const;
 
     void addLayerHitTestRects(LayerHitTestRects&) const;
 
     // Compute rects only for this layer
     void computeSelfHitTestRects(LayerHitTestRects&) const;
 
     // FIXME: This should probably return a ScrollableArea but a lot of internal methods are mistakenly exposed.
     DeprecatedPaintLayerScrollableArea* scrollableArea() const { return m_scrollableArea.get(); }
@@ skipping 344 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::DeprecatedPaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h