Update drag images to paint from the nearest self painting layer

third_party/WebKit/Source/core/paint/PaintLayer.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 592 matching lines @@
     void setHasCompositingDescendant(bool);
 
     bool shouldIsolateCompositedDescendants() const { ASSERT(isAllowedToQueryCompositingState()); return m_shouldIsolateCompositedDescendants; }
     void setShouldIsolateCompositedDescendants(bool);
 
     void updateDescendantDependentFlags();
 
     void updateOrRemoveFilterEffectBuilder();
 
     void updateSelfPaintingLayer();
+    // This is O(depth) so avoid calling this in loops. Instead use optimizations like
+    // those in PaintInvalidationState.
+    PaintLayer* enclosingSelfPaintingLayer();
 
     PaintLayer* enclosingTransformedAncestor() const;
     LayoutPoint computeOffsetFromTransformedAncestor() const;
 
     void didUpdateNeedsCompositedScrolling();
 
     bool hasSelfPaintingLayerDescendant() const
     {
         if (m_hasSelfPaintingLayerDescendantDirty)
             updateHasSelfPaintingLayerDescendant();
@@ skipping 248 matching lines @@
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showLayerTree(const blink::PaintLayer*);
 void showLayerTree(const blink::LayoutObject*);
 #endif
 
 #endif // Layer_h