Fix focus navigation for nested slot case

third_party/WebKit/Source/core/page/FocusController.cpp

 /*
  * Copyright (C) 2006, 2007 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nuanti Ltd.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  * 1. Redistributions of source code must retain the above copyright
  *    notice, this list of conditions and the following disclaimer.
  * 2. Redistributions in binary form must reproduce the above copyright
@@ skipping 153 matching lines @@
     while (m_current &&
            (SlotScopedTraversal::isSlotScoped(*m_current) ||
             ScopedFocusNavigation::isSlotFallbackScoped(*m_current)))
       m_current = ElementTraversal::previous(*m_current);
   }
 }
 
 void ScopedFocusNavigation::moveToFirst() {
   if (m_rootSlot) {
     if (!m_slotFallbackTraversal) {
-      HeapVector<Member<Node>> assignedNodes = m_rootSlot->assignedNodes();
-      for (auto assignedNode : assignedNodes) {
-        if (assignedNode->isElementNode()) {
-          m_current = toElement(assignedNode);
-          break;
-        }
-      }
+      m_current = SlotScopedTraversal::firstAssignedToSlot(*m_rootSlot);
     } else {
       Element* first = ElementTraversal::firstChild(*m_rootSlot);
       while (first &&
              !ScopedFocusNavigation::isSlotFallbackScopedForThisSlot(
                  *m_rootSlot, *first))
         first = ElementTraversal::next(*first, m_rootSlot);
       m_current = first;
     }
   } else {
     Element* first = m_rootNode->isElementNode()
                          ? &toElement(*m_rootNode)
                          : ElementTraversal::next(*m_rootNode);
     while (first && (SlotScopedTraversal::isSlotScoped(*first) ||
                      ScopedFocusNavigation::isSlotFallbackScoped(*first)))
       first = ElementTraversal::next(*first, m_rootNode);
     m_current = first;
   }
 }
 
 void ScopedFocusNavigation::moveToLast() {
   if (m_rootSlot) {
     if (!m_slotFallbackTraversal) {
-      HeapVector<Member<Node>> assignedNodes = m_rootSlot->assignedNodes();
-      for (auto assignedNode = assignedNodes.rbegin();
-           assignedNode != assignedNodes.rend(); ++assignedNode) {
-        if ((*assignedNode)->isElementNode()) {
-          m_current =
-              ElementTraversal::lastWithinOrSelf(*toElement(*assignedNode));
-          break;
-        }
-      }
+      m_current = SlotScopedTraversal::lastAssignedToSlot(*m_rootSlot);
     } else {
       Element* last = ElementTraversal::lastWithin(*m_rootSlot);
       while (last &&
              !ScopedFocusNavigation::isSlotFallbackScopedForThisSlot(
                  *m_rootSlot, *last))
         last = ElementTraversal::previous(*last, m_rootSlot);
       m_current = last;
     }
   } else {
     Element* last = ElementTraversal::lastWithin(*m_rootNode);
@@ skipping 1203 matching lines @@
 
   return consumed;
 }
 
 DEFINE_TRACE(FocusController) {
   visitor->trace(m_page);
   visitor->trace(m_focusedFrame);
 }
 
 }  // namespace blink