Fix compiling of sync on linux.

chrome/browser/sync/util/path_helpers.h

 // Copyright (c) 2009 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.
 
 #ifndef CHROME_BROWSER_SYNC_UTIL_PATH_HELPERS_H_
 #define CHROME_BROWSER_SYNC_UTIL_PATH_HELPERS_H_
 
 #include <algorithm>
 #include <iterator>
 #include <string>
@@ skipping 54 matching lines @@
   typename StringType::size_type segment_end_;
   StringType value_;
 };
 
 // NOTE: The functions (Strip)LastPathSegment always return values without a
 // trailing slash.
 PathString LastPathSegment(const PathString& path);
 std::string LastPathSegment(const std::string& path);
 PathString AppendSlash(const PathString& path);
 PathString GetFullPath(const PathString& path);
-PathString LowercasePath(const PathString& path);
 PathString ExpandTilde(const PathString& path);
 
 inline bool HasSuffixPathString(const PathString& str,
                                 const PathString& suffix) {
   return str.find(suffix, str.size() - suffix.size()) != PathString::npos;
 }
 
 inline PathString StripSuffixPathString(const PathString& str,
                                         const PathString& suffix) {
   PathString ret(str);
@@ skipping 10 matching lines @@
 // Makes a path component legal for your OS, but doesn't handle collisions
 // with other files in the same directory. it can do this by removing
 // illegal characters and adding ~1 before the first '.' in the filename.
 // returns PSTR("") if the name is fine as-is
 // on mac/linux we let names stay unicode normalization form C in the system
 // and convert to another normal form in fuse handlers. but, if a '/' is in
 // a filename, we handle it here.
 PathString MakePathComponentOSLegal(const PathString& component);
 
 #endif  // CHROME_BROWSER_SYNC_UTIL_PATH_HELPERS_H_