Merge to XFA: Add ostream helpers for FX String classes.

testing/fx_string_testhelpers.h

+// Copyright 2014 PDFium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef TESTING_FX_STRING_TESTHELPERS_H_
+#define TESTING_FX_STRING_TESTHELPERS_H_
+
+#include <ostream>
+
+#include "../core/include/fxcrt/fx_basic.h"
+
+// Output stream operator so GTEST macros work with FX strings.
+std::ostream& operator<<(std::ostream& out, const CFX_ByteStringC& str);
+std::ostream& operator<<(std::ostream& out, const CFX_ByteString& str);
+std::ostream& operator<<(std::ostream& out, const CFX_WideStringC& str);
+std::ostream& operator<<(std::ostream& out, const CFX_WideString& str);
+
+#endif  // TESTING_FX_STR_TESTHELPERS_H_
+