Node.contains should return true for nodes in Shadow DOM.

Source/core/dom/Node.h

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2001 Dirk Mueller (mueller@kde.org)
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008, 2009 Torch Mobile Inc. All rights reserved. (http://www.torchmobile.com/)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
@@ skipping 499 matching lines @@
     virtual bool childTypeAllowed(NodeType) const { return false; }
     unsigned childNodeCount() const;
     Node* childNode(unsigned index) const;
 
     void checkSetPrefix(const AtomicString& prefix, ExceptionCode&);
     bool isDescendantOf(const Node*) const;
     bool contains(const Node*) const;
     bool containsIncludingShadowDOM(const Node*) const;
     bool containsIncludingHostElements(const Node*) const;
 
+    // FIXME: Remove this when crbug.com/265716 cleans up contains semantics.
+    bool bindingsContains(const Node* node) const { return containsIncludingShadowDOM(node); }
+
     // Used to determine whether range offsets use characters or node indices.
     virtual bool offsetInCharacters() const;
     // Number of DOM 16-bit units contained in node. Note that rendered text length can be different - e.g. because of
     // css-transform:capitalize breaking up precomposed characters and ligatures.
     virtual int maxCharacterOffset() const;
 
     // Whether or not a selection can be started in this object
     virtual bool canStartSelection() const;
 
     // Getting points into and out of screen space
@@ skipping 403 matching lines @@
 
 } //namespace
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const WebCore::Node*);
 void showNodePath(const WebCore::Node*);
 #endif
 
 #endif