Introduce Node::containingTreeScope(), which asserts that the node's root is a tree scope

third_party/WebKit/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) 2004-2011, 2014 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 461 matching lines @@
     {
         return treeScope().document();
     }
 
     TreeScope& treeScope() const
     {
         DCHECK(m_treeScope);
         return *m_treeScope;
     }
 
+    TreeScope& rootTreeScope() const
+    {
+        DCHECK(isInTreeScope());
+        return *m_treeScope;
+    }
+
     bool inActiveDocument() const;
 
     // Returns true if this node is associated with a shadow-including document and is in its associated document's
     // node tree, false otherwise.
     bool inShadowIncludingDocument() const
     {
         return getFlag(InDocumentFlag);
     }
     bool isInShadowTree() const { return getFlag(IsInShadowTreeFlag); }
     bool isInTreeScope() const { return getFlag(static_cast<NodeFlags>(InDocumentFlag | IsInShadowTreeFlag)); }
@@ skipping 438 matching lines @@
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showNode(const blink::Node*);
 void showTree(const blink::Node*);
 void showNodePath(const blink::Node*);
 #endif
 
 #endif // Node_h