Get rid of redundant member function PositionAlgorithm<Strategy>::{upstream,downstream}

Source/core/editing/commands/InsertListCommand.cpp

 /*
  * Copyright (C) 2006, 2010 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 377 matching lines @@
             RefPtrWillBeRawPtr<HTMLBRElement> placeholder = insertBlockPlaceholder(start.deepEquivalent());
             start = VisiblePosition(positionBeforeNode(placeholder.get()));
             end = start;
         }
 
         // Insert the list at a position visually equivalent to start of the
         // paragraph that is being moved into the list.
         // Try to avoid inserting it somewhere where it will be surrounded by
         // inline ancestors of start, since it is easier for editing to produce
         // clean markup when inline elements are pushed down as far as possible.
-        Position insertionPos(start.deepEquivalent().upstream());
+        Position insertionPos(mostBackwardCaretPosition(start.deepEquivalent()));
         // Also avoid the containing list item.
         Node* listChild = enclosingListChild(insertionPos.anchorNode());
         if (isHTMLLIElement(listChild))
             insertionPos = positionInParentBeforeNode(*listChild);
 
         insertNodeAt(listElement, insertionPos);
 
         // We inserted the list at the start of the content we're about to move
         // Update the start of content, so we don't try to move the list into itself.  bug 19066
         // Layout is necessary since start's node's inline layoutObjects may have been destroyed by the insertion
@@ skipping 18 matching lines @@
     return listElement;
 }
 
 DEFINE_TRACE(InsertListCommand)
 {
     visitor->trace(m_listElement);
     CompositeEditCommand::trace(visitor);
 }
 
 }