Deprecate file_util::AppendToPath() on non-Windows.

base/file_util_deprecated.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.
 
 // We're trying to transition away from paths as wstrings into using
 // FilePath objects.  This file contains declarations of deprecated
 // functions.  By hiding them here rather in the main header, we hope
 // to discourage callers.
 
 // See file_util.h for documentation on all functions that don't have
@@ skipping 36 matching lines @@
 bool ReadFileToString(const std::wstring& path, std::string* contents);
 bool GetTempDir(std::wstring* path);
 bool GetFileSize(const std::wstring& file_path, int64* file_size);
 bool GetFileInfo(const std::wstring& file_path, FileInfo* info);
 FILE* OpenFile(const std::string& filename, const char* mode);
 FILE* OpenFile(const std::wstring& filename, const char* mode);
 int ReadFile(const std::wstring& filename, char* data, int size);
 int WriteFile(const std::wstring& filename, const char* data, int size);
 bool GetCurrentDirectory(std::wstring* path);
 
-// Successfully deprecated on non-Windows, but Win-specific callers remain.
+// Functions successfully deprecated on non-Windows, but Win-specific
+// callers remain.
 #if defined(OS_WIN)
 // Returns the directory component of a path, without the trailing
 // path separator, or an empty string on error. The function does not
 // check for the existence of the path, so if it is passed a directory
 // without the trailing \, it will interpret the last component of the
 // path as a file and chomp it. This does not support relative paths.
 // Examples:
 // path == "C:\pics\jojo.jpg",     returns "C:\pics"
 // path == "C:\Windows\system32\", returns "C:\Windows\system32"
 // path == "C:\Windows\system32",  returns "C:\Windows"
 // Deprecated. Use FilePath's DirName() instead.
 std::wstring GetDirectoryFromPath(const std::wstring& path);
+
+// Appends new_ending to path, adding a separator between the two if necessary.
+void AppendToPath(std::wstring* path, const std::wstring& new_ending);
 #endif
 
 }
 
 #endif  // BASE_FILE_UTIL_DEPRECATED_H_