Move dir_reader to base/files

base/dir_reader_posix.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.
-
-#ifndef BASE_DIR_READER_POSIX_H_
-#define BASE_DIR_READER_POSIX_H_
-#pragma once
-
-#include "build/build_config.h"
-
-// This header provides a class, DirReaderPosix, which allows one to open and
-// read from directories without allocating memory. For the interface, see
-// the generic fallback in dir_reader_fallback.h.
-
-// Mac note: OS X has getdirentries, but it only works if we restrict Chrome to
-// 32-bit inodes. There is a getdirentries64 syscall in 10.6, but it's not
-// wrapped and the direct syscall interface is unstable. Using an unstable API
-// seems worse than falling back to enumerating all file descriptors so we will
-// probably never implement this on the Mac.
-
-#if defined(OS_LINUX)
-#include "base/dir_reader_linux.h"
-#else
-#include "base/dir_reader_fallback.h"
-#endif
-
-namespace base {
-
-#if defined(OS_LINUX)
-typedef DirReaderLinux DirReaderPosix;
-#else
-typedef DirReaderFallback DirReaderPosix;
-#endif
-
-}  // namespace base
-
-#endif // BASE_DIR_READER_POSIX_H_