Port flush_cache tool.

base/test_file_util_linux.cc

 // Copyright (c) 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/test_file_util.h"
 
 #include <fcntl.h>
 #include <sys/stat.h>
 #include <sys/types.h>
 
 #include "base/file_path.h"
 
 namespace file_util {
 
-bool EvictFileFromSystemCache(const wchar_t* file) {
-  FilePath fpath = FilePath::FromWStringHack(file);
-  int fd = open(fpath.value().c_str(), O_RDONLY);
+bool EvictFileFromSystemCache(const FilePath& file) {
+  int fd = open(file.value().c_str(), O_RDONLY);
   if (fd < 0)
     return false;
   if (fdatasync(fd) != 0)
     return false;
   if (posix_fadvise(fd, 0, 0, POSIX_FADV_DONTNEED) != 0)
     return false;
   close(fd);
   return true;
 }
 
 }  // namespace file_util