Get rid of TreeBoundaryCrossingRules.

Source/core/dom/shadow/ShadowRoot.cpp

 /*
  * Copyright (C) 2011 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 137 matching lines @@
     recalcChildStyle(change);
     clearChildNeedsStyleRecalc();
 }
 
 void ShadowRoot::attach(const AttachContext& context)
 {
     StyleResolverParentScope parentScope(*this);
     DocumentFragment::attach(context);
 }
 
+void ShadowRoot::detach(const AttachContext& context)
+{
+    TreeScope::clearComposedParent();
+    DocumentFragment::detach(context);
+}
+
 Node::InsertionNotificationRequest ShadowRoot::insertedInto(ContainerNode* insertionPoint)
 {
     DocumentFragment::insertedInto(insertionPoint);
 
     if (!insertionPoint->inDocument() || !isOldest())
         return InsertionDone;
 
     // FIXME: When parsing <video controls>, insertedInto() is called many times without invoking removedFrom.
     // For now, we check m_registeredWithParentShadowroot. We would like to ASSERT(!m_registeredShadowRoot) here.
     // https://bugs.webkit.org/show_bug.cig?id=101316
@@ skipping 157 matching lines @@
 DEFINE_TRACE(ShadowRoot)
 {
     visitor->trace(m_prev);
     visitor->trace(m_next);
     visitor->trace(m_shadowRootRareData);
     TreeScope::trace(visitor);
     DocumentFragment::trace(visitor);
 }
 
 }