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

Source/core/editing/commands/InsertParagraphSeparatorCommand.cpp

 /*
  * Copyright (C) 2005, 2006 Apple Computer, 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 165 matching lines @@
         || isTableCell(startBlock.get())
         || isHTMLFormElement(*startBlock)
         // FIXME: If the node is hidden, we don't have a canonical position so we will do the wrong thing for tables and <hr>. https://bugs.webkit.org/show_bug.cgi?id=40342
         || (!canonicalPos.isNull() && isRenderedTableElement(canonicalPos.anchorNode()))
         || (!canonicalPos.isNull() && isHTMLHRElement(*canonicalPos.anchorNode()))) {
         applyCommandToComposite(InsertLineBreakCommand::create(document()));
         return;
     }
 
     // Use the leftmost candidate.
-    insertionPosition = insertionPosition.upstream();
+    insertionPosition = mostBackwardCaretPosition(insertionPosition);
     if (!isVisuallyEquivalentCandidate(insertionPosition))
-        insertionPosition = insertionPosition.downstream();
+        insertionPosition = mostForwardCaretPosition(insertionPosition);
 
     // Adjust the insertion position after the delete
     insertionPosition = positionAvoidingSpecialElementBoundary(insertionPosition);
     VisiblePosition visiblePos(insertionPosition, affinity);
     calculateStyleBeforeInsertion(insertionPosition);
 
     //---------------------------------------------------------------------
     // Handle special case of typing return on an empty list item
     if (breakOutOfEmptyListItem())
         return;
@@ skipping 84 matching lines @@
             ASSERT(startBlock->hasChildren());
             refNode = startBlock->firstChild();
         } else if (insertionPosition.anchorNode() == startBlock && nestNewBlock) {
             refNode = NodeTraversal::childAt(*startBlock, insertionPosition.computeEditingOffset());
             ASSERT(refNode); // must be true or we'd be in the end of block case
         } else {
             refNode = insertionPosition.anchorNode();
         }
 
         // find ending selection position easily before inserting the paragraph
-        insertionPosition = insertionPosition.downstream();
+        insertionPosition = mostForwardCaretPosition(insertionPosition);
 
         if (refNode)
             insertNodeBefore(blockToInsert, refNode);
 
         // Recreate the same structure in the new paragraph.
 
         WillBeHeapVector<RefPtrWillBeMember<Element>> ancestors;
         getAncestorsInsideBlock(positionAvoidingSpecialElementBoundary(positionOutsideTabSpan(insertionPosition)).anchorNode(), startBlock.get(), ancestors);
 
         appendBlockPlaceholder(cloneHierarchyUnderNewBlock(ancestors, blockToInsert));
@@ skipping 17 matching lines @@
         // If the insertion point is a break element, there is nothing else
         // we need to do.
         if (visiblePos.deepEquivalent().anchorNode()->layoutObject()->isBR()) {
             setEndingSelection(VisibleSelection(insertionPosition, TextAffinity::Downstream, endingSelection().isDirectional()));
             return;
         }
     }
 
     // Move downstream. Typing style code will take care of carrying along the
     // style of the upstream position.
-    insertionPosition = insertionPosition.downstream();
+    insertionPosition = mostForwardCaretPosition(insertionPosition);
 
     // At this point, the insertionPosition's node could be a container, and we want to make sure we include
     // all of the correct nodes when building the ancestor list.  So this needs to be the deepest representation of the position
     // before we walk the DOM tree.
     insertionPosition = positionOutsideTabSpan(VisiblePosition(insertionPosition).deepEquivalent());
 
     // If the returned position lies either at the end or at the start of an element that is ignored by editing
     // we should move to its upstream or downstream position.
     if (editingIgnoresContent(insertionPosition.anchorNode())) {
         if (insertionPosition.atLastEditingPositionForNode())
-            insertionPosition = insertionPosition.downstream();
+            insertionPosition = mostForwardCaretPosition(insertionPosition);
         else if (insertionPosition.atFirstEditingPositionForNode())
-            insertionPosition = insertionPosition.upstream();
+            insertionPosition = mostBackwardCaretPosition(insertionPosition);
     }
 
     // Make sure we do not cause a rendered space to become unrendered.
-    // FIXME: We need the affinity for pos, but pos.downstream() does not give it
+    // FIXME: We need the affinity for pos, but mostForwardCaretPosition does not give it
     Position leadingWhitespace = leadingWhitespacePosition(insertionPosition, VP_DEFAULT_AFFINITY);
     // FIXME: leadingWhitespacePosition is returning the position before preserved newlines for positions
     // after the preserved newline, causing the newline to be turned into a nbsp.
     if (leadingWhitespace.isNotNull() && leadingWhitespace.anchorNode()->isTextNode()) {
         Text* textNode = toText(leadingWhitespace.anchorNode());
         ASSERT(!textNode->layoutObject() || textNode->layoutObject()->style()->collapseWhiteSpace());
         replaceTextInNodePreservingMarkers(textNode, leadingWhitespace.computeOffsetInContainerNode(), 1, nonBreakingSpaceString());
     }
 
     // Split at pos if in the middle of a text node.
@@ skipping 74 matching lines @@
 }
 
 DEFINE_TRACE(InsertParagraphSeparatorCommand)
 {
     visitor->trace(m_style);
     CompositeEditCommand::trace(visitor);
 }
 
 
 } // namespace blink