Introduce Position::nodeAsRangeLastNode

Source/core/dom/Position.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2009 Apple 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:
  * 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
  *    notice, this list of conditions and the following disclaimer in the
@@ skipping 302 matching lines @@
         return toOffsetInAnchor().nodeAsRangeFirstNode();
     if (m_anchorNode->offsetInCharacters())
         return m_anchorNode.get();
     if (Node* child = Strategy::childAt(*m_anchorNode, m_offset))
         return child;
     if (!m_offset)
         return m_anchorNode.get();
     return Strategy::nextSkippingChildren(*m_anchorNode);
 }
 
+template <typename Strategy>
+Node* PositionAlgorithm<Strategy>::nodeAsRangeLastNode() const
+{
+    if (isNull())
+        return nullptr;
+    if (Node* pastLastNode = nodeAsRangePastLastNode())
+        return Strategy::previous(*pastLastNode);
+    return &Strategy::lastWithinOrSelf(*containerNode());
+}
+
 // An implementation of |Range::pastLastNode()|.
 template <typename Strategy>
 Node* PositionAlgorithm<Strategy>::nodeAsRangePastLastNode() const
 {
     if (!m_anchorNode)
         return nullptr;
     if (m_anchorType != PositionIsOffsetInAnchor)
         return toOffsetInAnchor().nodeAsRangePastLastNode();
     if (m_anchorNode->offsetInCharacters())
         return Strategy::nextSkippingChildren(*m_anchorNode);
@@ skipping 1192 matching lines @@
 
 void showTree(const blink::Position* pos)
 {
     if (pos)
         pos->showTreeForThis();
     else
         fprintf(stderr, "Cannot showTree for (nil)\n");
 }
 
 #endif