Make VisiblePosition constructor to canonicalize a position in composed tree

Source/core/dom/Position.h

 /*
  * Copyright (C) 2004, 2006, 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 435 matching lines @@
 
 template <typename Strategy>
 typename Strategy::PositionType PositionAlgorithm<Strategy>::lastPositionInOrAfterNode(Node* node)
 {
     if (!node)
         return PositionType();
     return Strategy::editingIgnoresContent(node) ? afterNode(node) : lastPositionInNode(node);
 }
 
 PositionInComposedTree toPositionInComposedTree(const Position&);
+Position toPositionInDOMTree(const Position&);
 Position toPositionInDOMTree(const PositionInComposedTree&);
 
 } // namespace blink
 
 #ifndef NDEBUG
 // Outside the WebCore namespace for ease of invocation from gdb.
 void showTree(const blink::Position&);
 void showTree(const blink::Position*);
 #endif
 
 #endif // Position_h