posix: directories should only be readable by the user.

base/file_util.h

 // Copyright (c) 2006-2008 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 contains utility functions for dealing with the local
 // filesystem.
 
 #ifndef BASE_FILE_UTIL_H_
 #define BASE_FILE_UTIL_H_
 
@@ skipping 298 matching lines @@
 // TODO(erikkay): is this OK?
 // If success, return true and output the full path of the directory created.
 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
                             FilePath* new_temp_path);
 // Deprecated temporary compatibility function.
 bool CreateNewTempDirectory(const std::wstring& prefix,
                             std::wstring* new_temp_path);
 
 // Creates a directory, as well as creating any parent directories, if they
 // don't exist. Returns 'true' on successful creation, or if the directory
-// already exists.
+// already exists.  The directory is only readable by the current user.
 bool CreateDirectory(const FilePath& full_path);
 // Deprecated temporary compatibility function.
 bool CreateDirectory(const std::wstring& full_path);
 
 // Returns the file size. Returns true on success.
 bool GetFileSize(const FilePath& file_path, int64* file_size);
 // Deprecated temporary compatibility function.
 bool GetFileSize(const std::wstring& file_path, int64* file_size);
 
 // Used to hold information about a given file path.  See GetFileInfo below.
@@ skipping 183 matching lines @@
 
 // Renames a file using the SHFileOperation API to ensure that the target file
 // gets the correct default security descriptor in the new path.
 bool RenameFileAndResetSecurityDescriptor(
     const FilePath& source_file_path,
     const FilePath& target_file_path);
 
 }  // namespace file_util
 
 #endif  // BASE_FILE_UTIL_H_