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

Source/core/editing/commands/TypingCommand.cpp

 /*
  * Copyright (C) 2005, 2006, 2007, 2008 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 522 matching lines @@
 
         // Handle delete at beginning-of-block case.
         // Do nothing in the case that the caret is at the start of a
         // root editable element or at the start of a document.
         OwnPtrWillBeRawPtr<FrameSelection> selection = FrameSelection::create();
         selection->setSelection(endingSelection());
         selection->modify(FrameSelection::AlterationExtend, DirectionForward, granularity);
         if (killRing && selection->isCaret() && granularity != CharacterGranularity)
             selection->modify(FrameSelection::AlterationExtend, DirectionForward, CharacterGranularity);
 
-        Position downstreamEnd = endingSelection().end().downstream();
+        Position downstreamEnd = mostForwardCaretPosition(endingSelection().end());
         VisiblePosition visibleEnd = endingSelection().visibleEnd();
         Node* enclosingTableCell = enclosingNodeOfType(visibleEnd.deepEquivalent(), &isTableCell);
         if (enclosingTableCell && visibleEnd.deepEquivalent() == VisiblePosition(lastPositionInNode(enclosingTableCell)).deepEquivalent())
             return;
         if (visibleEnd.deepEquivalent() == endOfParagraph(visibleEnd).deepEquivalent())
-            downstreamEnd = visibleEnd.next(CannotCrossEditingBoundary).deepEquivalent().downstream();
+            downstreamEnd = mostForwardCaretPosition(visibleEnd.next(CannotCrossEditingBoundary).deepEquivalent());
         // When deleting tables: Select the table first, then perform the deletion
         if (isRenderedTableElement(downstreamEnd.computeContainerNode()) && downstreamEnd.computeOffsetInContainerNode() <= caretMinOffset(downstreamEnd.computeContainerNode())) {
             setEndingSelection(VisibleSelection(endingSelection().end(), positionAfterNode(downstreamEnd.computeContainerNode()), TextAffinity::Downstream, endingSelection().isDirectional()));
             typingAddedToOpenCommand(ForwardDeleteKey);
             return;
         }
 
         // deleting to end of paragraph when at end of paragraph needs to merge the next paragraph (if any)
         if (granularity == ParagraphBoundary && selection->selection().isCaret() && isEndOfParagraph(selection->selection().visibleEnd()))
             selection->modify(FrameSelection::AlterationExtend, DirectionForward, CharacterGranularity);
@@ skipping 66 matching lines @@
     ASSERT_NOT_REACHED();
     m_preservesTypingStyle = false;
 }
 
 bool TypingCommand::isTypingCommand() const
 {
     return true;
 }
 
 } // namespace blink