Make assignedSlot return null for a slot in a closed shadow tree

third_party/WebKit/Source/core/dom/shadow/ElementShadow.h

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
  * notice, this list of conditions and the following disclaimer.
  *     * Neither the name of Google Inc. nor the names of its
@@ skipping 66 matching lines @@
 
     void distributeIfNeeded();
     void setNeedsDistributionRecalc();
 
     const InsertionPoint* finalDestinationInsertionPointFor(const Node*) const;
     const DestinationInsertionPoints* destinationInsertionPointsFor(const Node*) const;
 
     void didDistributeNode(const Node*, InsertionPoint*);
 
     bool isV1() const { return youngestShadowRoot().isV1(); };
+    bool isOpen() const { return youngestShadowRoot().isOpen(); };
 
     DECLARE_TRACE();
 
 private:
     ElementShadow();
 
 #if !ENABLE(OILPAN)
     void removeDetachedShadowRoots();
 #endif
 
@@ skipping 65 matching lines @@
 inline void ElementShadow::distributeIfNeeded()
 {
     if (m_needsDistributionRecalc)
         distribute();
     m_needsDistributionRecalc = false;
 }
 
 } // namespace
 
 #endif