base: Get rid of a deprecated version of file_util::GetFileExtensionFromPath().

base/file_util.cc

 // 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.
 
 #include "base/file_util.h"
 
 #if defined(OS_WIN)
 #include <io.h>
 #endif
 #include <stdio.h>
@@ skipping 29 matching lines @@
   if (EndsWithSeparator(*path))
     return true;
 
   FilePath::StringType& path_str =
       const_cast<FilePath::StringType&>(path->value());
   path_str.append(&FilePath::kSeparators[0], 1);
 
   return true;
 }
 
-FilePath::StringType GetFileExtensionFromPath(const FilePath& path) {
-  FilePath::StringType file_name = path.BaseName().value();
-  const FilePath::StringType::size_type last_dot =
-      file_name.rfind(kExtensionSeparator);
-  return FilePath::StringType(last_dot == FilePath::StringType::npos ?
-                              FILE_PATH_LITERAL("") :
-                              file_name, last_dot+1);
-}
-
 void InsertBeforeExtension(FilePath* path, const FilePath::StringType& suffix) {
   FilePath::StringType& value =
       const_cast<FilePath::StringType&>(path->value());
 
   const FilePath::StringType::size_type last_dot =
       value.rfind(kExtensionSeparator);
   const FilePath::StringType::size_type last_separator =
       value.find_last_of(FilePath::StringType(FilePath::kSeparators));
 
   if (last_dot == FilePath::StringType::npos ||
@@ skipping 306 matching lines @@
 bool CopyDirectory(const std::wstring& from_path, const std::wstring& to_path,
                    bool recursive) {
   return CopyDirectory(FilePath::FromWStringHack(from_path),
                        FilePath::FromWStringHack(to_path),
                        recursive);
 }
 bool Delete(const std::wstring& path, bool recursive) {
   return Delete(FilePath::FromWStringHack(path), recursive);
 }
 std::wstring GetFileExtensionFromPath(const std::wstring& path) {
-  FilePath::StringType extension =
-      GetFileExtensionFromPath(FilePath::FromWStringHack(path));
-  return extension;
+  std::wstring file_name = FilePath(path).BaseName().value();
+  const std::wstring::size_type last_dot = file_name.rfind(kExtensionSeparator);
+  return std::wstring(last_dot == std::wstring::npos ? L""
+                                                     : file_name, last_dot + 1);
 }
 FILE* OpenFile(const std::wstring& filename, const char* mode) {
   return OpenFile(FilePath::FromWStringHack(filename), mode);
 }
 int ReadFile(const std::wstring& filename, char* data, int size) {
   return ReadFile(FilePath::FromWStringHack(filename), data, size);
 }
 int WriteFile(const std::wstring& filename, const char* data, int size) {
   return WriteFile(FilePath::FromWStringHack(filename), data, size);
 }
 #endif  // OS_WIN
 
 ///////////////////////////////////////////////
 // FileEnumerator
 //
 // Note: the main logic is in file_util_<platform>.cc
 
 bool FileEnumerator::ShouldSkip(const FilePath& path) {
   FilePath::StringType basename = path.BaseName().value();
   return IsDot(path) || (IsDotDot(path) && !(INCLUDE_DOT_DOT & file_type_));
 }
 
 }  // namespace