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

Source/core/layout/LayoutObject.cpp

Index: Source/core/layout/LayoutObject.cpp
diff --git a/Source/core/layout/LayoutObject.cpp b/Source/core/layout/LayoutObject.cpp
index 28c61e1fc62b67b095b35bab84d089161fb73d33..d7bca6f9b36a083013100d94928c77e30287351f 100644
--- a/Source/core/layout/LayoutObject.cpp
+++ b/Source/core/layout/LayoutObject.cpp
@@ -2992,10 +2992,10 @@ PositionWithAffinity LayoutObject::createPositionWithAffinity(int offset, TextAf
         if (!node->hasEditableStyle()) {
             // If it can be found, we prefer a visually equivalent position that is editable.
             const Position position = Position(node, offset);
-            Position candidate = position.downstream(CanCrossEditingBoundary);
+            Position candidate = mostForwardCaretPosition(position, CanCrossEditingBoundary);
             if (candidate.anchorNode()->hasEditableStyle())
                 return PositionWithAffinity(candidate, affinity);
-            candidate = position.upstream(CanCrossEditingBoundary);
+            candidate = mostBackwardCaretPosition(position, CanCrossEditingBoundary);
             if (candidate.anchorNode()->hasEditableStyle())
                 return PositionWithAffinity(candidate, affinity);
         }