Fix focus navigation for nested slot case

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

 // Copyright 2016 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef SlotScopedTraversal_h
 #define SlotScopedTraversal_h
 
+#include "core/CoreExport.h"
+
 namespace blink {
 
 class Element;
 class HTMLSlotElement;
 
-class SlotScopedTraversal {
+class CORE_EXPORT SlotScopedTraversal {
  public:
   static HTMLSlotElement* findScopeOwnerSlot(const Element&);
-  static Element* nearestAncestorAssignedToSlot(const Element&);
+  static Element* nearestInclusiveAncestorAssignedToSlot(const Element&);
   static Element* next(const Element&);
   static Element* previous(const Element&);
+  static Element* firstAssignedToSlot(HTMLSlotElement&);
+  static Element* lastAssignedToSlot(HTMLSlotElement&);
+
   static bool isSlotScoped(const Element&);
 };
 
 }  // namespace blink
 
 #endif