Templatize canonicalizeCandidate() in VisiblePosition

Source/core/editing/VisiblePosition.cpp

 /*
  * Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Portions Copyright (c) 2011 Motorola Mobility, 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
@@ skipping 524 matching lines @@
         return pos;
 
     // If this is not editable but |pos| has an editable root, skip to the end
     if (!highestRoot && highestRootOfPos)
         return VisiblePosition(Position(highestRootOfPos, Position::PositionIsAfterAnchor).parentAnchoredEquivalent());
 
     // That must mean that |pos| is not editable. Return the next position after pos that is in the same editable region as this position
     return firstEditableVisiblePositionAfterPositionInRoot(pos.deepEquivalent(), highestRoot);
 }
 
-static Position canonicalizeCandidate(const Position& candidate)
+template <typename PositionType>
+static PositionType canonicalizeCandidate(const PositionType& candidate)
 {
     if (candidate.isNull())
-        return Position();
+        return PositionType();
     ASSERT(candidate.isCandidate());
-    Position upstream = candidate.upstream();
+    PositionType upstream = candidate.upstream();
     if (upstream.isCandidate())
         return upstream;
     return candidate;
 }
 
 Position VisiblePosition::canonicalPosition(const Position& passedPosition)
 {
     // Sometimes updating selection positions can be extremely expensive and occur
     // frequently.  Often calling preventDefault on mousedown events can avoid
     // doing unnecessary text selection work.  http://crbug.com/472258.
@@ skipping 231 matching lines @@
     else
         fprintf(stderr, "Cannot showTree for (nil) VisiblePosition.\n");
 }
 
 void showTree(const blink::VisiblePosition& vpos)
 {
     vpos.showTreeForThis();
 }
 
 #endif