Move file_util to be POSIX-only

base/file_util.cc

-// Copyright 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.
-
-#include "base/file_util.h"
-
-#include <unistd.h>
-
-#include "base/posix/eintr_wrapper.h"
-
-namespace base {
-
-bool ReadFromFD(int fd, char* buffer, size_t bytes) {
-  size_t total_read = 0;
-  while (total_read < bytes) {
-    ssize_t bytes_read =
-        HANDLE_EINTR(read(fd, buffer + total_read, bytes - total_read));
-    if (bytes_read <= 0) {
-      break;
-    }
-    total_read += bytes_read;
-  }
-  return total_read == bytes;
-}
-
-}  // namespace base