Implement DownloadFile::Rename() for posix. Downloads work on linux!

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 136 matching lines @@
 // subdirectories and their contents as well.
 // Returns true if successful, false otherwise.
 //
 // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
 //          TO "rm -rf", SO USE WITH CAUTION.
 bool Delete(const FilePath& path, bool recursive);
 // Deprecated temporary compatibility function.
 bool Delete(const std::wstring& path, bool recursive);
 
 // Moves the given path, whether it's a file or a directory.
-// Returns true if successful, false otherwise.
+// If a simple rename is not possible, such as in the case where the paths are
+// on different volumes, this will attempt to copy and delete. Returns
+// true for success.
 bool Move(const FilePath& from_path, const FilePath& to_path);
 // Deprecated temporary compatibility function.
 bool Move(const std::wstring& from_path, const std::wstring& to_path);
 
 // Copies a single file. Use CopyDirectory to copy directories.
 bool CopyFile(const FilePath& from_path, const FilePath& to_path);
 // Deprecated temporary compatibility function.
 bool CopyFile(const std::wstring& from_path, const std::wstring& to_path);
 
 // Copies the given path, and optionally all subdirectories and their contents
@@ skipping 333 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_