Add unit test for ReplaceStringPlaceholders

base/string_util.h

 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 //
 // This file defines utility functions for working with strings.
 
 #ifndef BASE_STRING_UTIL_H_
 #define BASE_STRING_UTIL_H_
 #pragma once
 
@@ skipping 561 matching lines @@
 // characters defined by HTML 5). Each contiguous block of non-whitespace
 // characters is added to result.
 void SplitStringAlongWhitespace(const std::wstring& str,
                                 std::vector<std::wstring>* result);
 void SplitStringAlongWhitespace(const string16& str,
                                 std::vector<string16>* result);
 void SplitStringAlongWhitespace(const std::string& str,
                                 std::vector<std::string>* result);
 
 // Replace $1-$2-$3..$9 in the format string with |a|-|b|-|c|..|i| respectively.
-// Additionally, $$ is replaced by $. The offsets parameter here can
-// be NULL. This only allows you to use up to nine replacements.
+// Additionally, any number of consecutive '$' characters is replaced by that
+// number less one. Eg $$->$, $$$->$$, etc. The offsets parameter here can be
+// NULL. This only allows you to use up to nine replacements.
 string16 ReplaceStringPlaceholders(const string16& format_string,
                                    const std::vector<string16>& subst,
                                    std::vector<size_t>* offsets);
 
 std::string ReplaceStringPlaceholders(const base::StringPiece& format_string,
                                       const std::vector<std::string>& subst,
                                       std::vector<size_t>* offsets);
 
 // Single-string shortcut for ReplaceStringHolders.
 string16 ReplaceStringPlaceholders(const string16& format_string,
@@ skipping 38 matching lines @@
 #elif defined(WCHAR_T_IS_UTF32)
   typedef uint32 Unsigned;
 #endif
 };
 template<>
 struct ToUnsigned<short> {
   typedef unsigned short Unsigned;
 };
 
 #endif  // BASE_STRING_UTIL_H_