Revert of [Editing][Codehealth] Replace Position::uptream/downstream to mostBackward/ForwardCaretPosition.

Source/core/layout/HitTestResult.cpp

 /*
  * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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,
@@ skipping 145 matching lines @@
 }
 
 PositionWithAffinity HitTestResult::position() const
 {
     if (!m_innerPossiblyPseudoNode)
         return PositionWithAffinity();
     LayoutObject* layoutObject = this->layoutObject();
     if (!layoutObject)
         return PositionWithAffinity();
     if (m_innerPossiblyPseudoNode->isPseudoElement() && m_innerPossiblyPseudoNode->pseudoId() == BEFORE)
-        return mostBackwardCaretPosition(Position(m_innerNode, PositionAnchorType::BeforeChildren));
+        return Position(m_innerNode, PositionAnchorType::BeforeChildren).downstream();
     return layoutObject->positionForPoint(localPoint());
 }
 
 LayoutObject* HitTestResult::layoutObject() const
 {
     return m_innerNode ? m_innerNode->layoutObject() : 0;
 }
 
 void HitTestResult::setToShadowHostIfInUserAgentShadowRoot()
 {
@@ skipping 346 matching lines @@
     else if (isHTMLMapElement(m_innerNode))
         imageMapImageElement = toHTMLMapElement(m_innerNode)->imageElement();
 
     if (!imageMapImageElement)
         return m_innerNode.get();
 
     return imageMapImageElement;
 }
 
 } // namespace blink