Re-introduce printers for Node, Position, PositionAnchorType in GTest

Source/core/editing/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 372 matching lines @@
 {
     return position;
 }
 
 template <>
 inline PositionInComposedTree fromPositionInDOMTree<EditingInComposedTreeStrategy>(const Position& position)
 {
     return toPositionInComposedTree(position);
 }
 
+// These printers are available only for testing in "webkit_unit_tests", and
+// implemented in "core/testing/CoreTestPrinters.cpp".
+std::ostream& operator<<(std::ostream&, const Node&);
+std::ostream& operator<<(std::ostream&, const Node*);
+
+std::ostream& operator<<(std::ostream&, PositionAnchorType);
+std::ostream& operator<<(std::ostream&, const Position&);
+std::ostream& operator<<(std::ostream&, 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