Get rid of a redundant argument DOWNSTREAM from PositionWithAffinity constructor call sites

Source/core/layout/LayoutBlock.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2007 David Smith (catfish.man@gmail.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010, 2011 Apple Inc. All rights reserved.
  * Copyright (C) Research In Motion Limited 2010. All rights reserved.
  *
  * 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
@@ skipping 1869 matching lines @@
         if (moveCaretToBoundary) {
             LayoutUnit firstRootBoxWithChildrenTop = std::min<LayoutUnit>(firstRootBoxWithChildren->selectionTop(), firstRootBoxWithChildren->logicalTop());
             if (pointInLogicalContents.y() < firstRootBoxWithChildrenTop
                 || (blocksAreFlipped && pointInLogicalContents.y() == firstRootBoxWithChildrenTop)) {
                 InlineBox* box = firstRootBoxWithChildren->firstLeafChild();
                 if (box->isLineBreak()) {
                     if (InlineBox* newBox = box->nextLeafChildIgnoringLineBreak())
                         box = newBox;
                 }
                 // y coordinate is above first root line box, so return the start of the first
-                return PositionWithAffinity(positionForBox(box, true), DOWNSTREAM);
+                return PositionWithAffinity(positionForBox(box, true));
             }
         }
 
         // pass the box a top position that is inside it
         LayoutPoint point(pointInLogicalContents.x(), closestBox->root().blockDirectionPointInLine());
         if (!isHorizontalWritingMode())
             point = point.transposedPoint();
         if (closestBox->layoutObject().isReplaced())
             return positionForPointRespectingEditingBoundaries(this, &toLayoutBox(closestBox->layoutObject()), point);
         return closestBox->layoutObject().positionForPoint(point);
     }
 
     if (lastRootBoxWithChildren) {
         // We hit this case for Mac behavior when the Y coordinate is below the last box.
         ASSERT(moveCaretToBoundary);
         InlineBox* logicallyLastBox;
         if (lastRootBoxWithChildren->getLogicalEndBoxWithNode(logicallyLastBox))
-            return PositionWithAffinity(positionForBox(logicallyLastBox, false), DOWNSTREAM);
+            return PositionWithAffinity(positionForBox(logicallyLastBox, false));
     }
 
     // Can't reach this. We have a root line box, but it has no kids.
     // FIXME: This should ASSERT_NOT_REACHED(), but clicking on placeholder text
     // seems to hit this code path.
     return createPositionWithAffinity(0, DOWNSTREAM);
 }
 
 static inline bool isChildHitTestCandidate(LayoutBox* box)
 {
@@ skipping 999 matching lines @@
 void LayoutBlock::showLineTreeAndMark(const InlineBox* markedBox1, const char* markedLabel1, const InlineBox* markedBox2, const char* markedLabel2, const LayoutObject* obj) const
 {
     showLayoutObject();
     for (const RootInlineBox* root = firstRootBox(); root; root = root->nextRootBox())
         root->showLineTreeAndMark(markedBox1, markedLabel1, markedBox2, markedLabel2, obj, 1);
 }
 
 #endif
 
 } // namespace blink