Revert "Implement proposed shadow tree cascade order."

Source/core/css/TreeBoundaryCrossingRules.h

Index: Source/core/css/TreeBoundaryCrossingRules.h
diff --git a/Source/core/css/TreeBoundaryCrossingRules.h b/Source/core/css/TreeBoundaryCrossingRules.h
new file mode 100644
index 0000000000000000000000000000000000000000..70cf65eff2f63aa2e0e6fb7c6fe8f3dc022767bf
--- /dev/null
+++ b/Source/core/css/TreeBoundaryCrossingRules.h
@@ -0,0 +1,55 @@
+/*
+ * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
+ * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
+ * Copyright (C) 2013 Google Inc. All rights reserved.
+ *
+ * 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
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public License
+ * along with this library; see the file COPYING.LIB.  If not, write to
+ * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+ * Boston, MA 02110-1301, USA.
+ *
+ */
+
+#ifndef TreeBoundaryCrossingRules_h
+#define TreeBoundaryCrossingRules_h
+
+#include "core/dom/DocumentOrderedList.h"
+
+#include "wtf/OwnPtr.h"
+#include "wtf/RefPtr.h"
+#include "wtf/Vector.h"
+
+namespace blink {
+
+class ContainerNode;
+class Element;
+class ElementRuleCollector;
+
+class TreeBoundaryCrossingRules final {
+    DISALLOW_ALLOCATION();
+public:
+    void addScope(ContainerNode&);
+    void removeScope(const ContainerNode&);
+    void collectTreeBoundaryCrossingRules(Element*, ElementRuleCollector&, bool includeEmptyRules);
+
+    DECLARE_TRACE();
+
+private:
+    size_t size() const { return m_scopingNodes.size(); }
+
+    DocumentOrderedList m_scopingNodes;
+};
+
+} // namespace blink
+
+#endif // TreeBoundaryCrossingRules_h