Have NodeTraversal::previous*() take a reference

Source/core/editing/VisibleUnits.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 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 1097 matching lines @@
     Node* highestRoot = highestEditableRoot(p);
     int offset = p.deprecatedEditingOffset();
     Position::AnchorType type = p.anchorType();
 
     Node* n = startNode;
     while (n) {
         if (boundaryCrossingRule == CannotCrossEditingBoundary && !Position::nodeIsUserSelectAll(n) && n->rendererIsEditable() != startNode->rendererIsEditable())
             break;
         if (boundaryCrossingRule == CanSkipOverEditingBoundary) {
             while (n && n->rendererIsEditable() != startNode->rendererIsEditable())
-                n = NodeTraversal::previousPostOrder(n, startBlock);
+                n = NodeTraversal::previousPostOrder(*n, startBlock);
             if (!n || !n->isDescendantOf(highestRoot))
                 break;
         }
         RenderObject* r = n->renderer();
         if (!r) {
-            n = NodeTraversal::previousPostOrder(n, startBlock);
+            n = NodeTraversal::previousPostOrder(*n, startBlock);
             continue;
         }
         RenderStyle* style = r->style();
         if (style->visibility() != VISIBLE) {
-            n = NodeTraversal::previousPostOrder(n, startBlock);
+            n = NodeTraversal::previousPostOrder(*n, startBlock);
             continue;
         }
 
         if (r->isBR() || isBlock(n))
             break;
 
         if (r->isText() && toRenderText(r)->renderedTextLength()) {
             ASSERT_WITH_SECURITY_IMPLICATION(n->isTextNode());
             type = Position::PositionIsOffsetInAnchor;
             if (style->preserveNewline()) {
                 RenderText* text = toRenderText(r);
                 int i = text->textLength();
                 int o = offset;
                 if (n == startNode && o < i)
                     i = max(0, o);
                 while (--i >= 0) {
                     if ((*text)[i] == '\n')
                         return VisiblePosition(Position(toText(n), i + 1), DOWNSTREAM);
                 }
             }
             node = n;
             offset = 0;
-            n = NodeTraversal::previousPostOrder(n, startBlock);
+            n = NodeTraversal::previousPostOrder(*n, startBlock);
         } else if (editingIgnoresContent(n) || isRenderedTable(n)) {
             node = n;
             type = Position::PositionIsBeforeAnchor;
-            n = n->previousSibling() ? n->previousSibling() : NodeTraversal::previousPostOrder(n, startBlock);
-        } else
-            n = NodeTraversal::previousPostOrder(n, startBlock);
+            n = n->previousSibling() ? n->previousSibling() : NodeTraversal::previousPostOrder(*n, startBlock);
+        } else {
+            n = NodeTraversal::previousPostOrder(*n, startBlock);
+        }
     }
 
     if (type == Position::PositionIsOffsetInAnchor) {
         ASSERT(type == Position::PositionIsOffsetInAnchor || !offset);
         return VisiblePosition(Position(node, offset, type), DOWNSTREAM);
     }
 
     return VisiblePosition(Position(node, type), DOWNSTREAM);
 }
 
@@ skipping 240 matching lines @@
 {
     return direction == LTR ? logicalStartOfLine(c) : logicalEndOfLine(c);
 }
 
 VisiblePosition rightBoundaryOfLine(const VisiblePosition& c, TextDirection direction)
 {
     return direction == LTR ? logicalEndOfLine(c) : logicalStartOfLine(c);
 }
 
 }