Move Posix file utils to the base namespace.

chrome/browser/chromeos/drive/file_cache.cc

Index: chrome/browser/chromeos/drive/file_cache.cc
diff --git a/chrome/browser/chromeos/drive/file_cache.cc b/chrome/browser/chromeos/drive/file_cache.cc
index f5c67517eb328c568dca35d9cc85df051acd0a58..9049eda94020ba56dd6cf21098250f79f3b9cc63 100644
--- a/chrome/browser/chromeos/drive/file_cache.cc
+++ b/chrome/browser/chromeos/drive/file_cache.cc
@@ -245,12 +245,12 @@ FileError FileCache::MarkAsMounted(const std::string& id,
 
   // Ensure the file is readable to cros_disks. See crbug.com/236994.
   base::FilePath path = GetCacheFilePath(id);
-  if (!file_util::SetPosixFilePermissions(
+  if (!base::SetPosixFilePermissions(
           path,
-          file_util::FILE_PERMISSION_READ_BY_USER |
-          file_util::FILE_PERMISSION_WRITE_BY_USER |
-          file_util::FILE_PERMISSION_READ_BY_GROUP |
-          file_util::FILE_PERMISSION_READ_BY_OTHERS))
+          base::FILE_PERMISSION_READ_BY_USER |
+          base::FILE_PERMISSION_WRITE_BY_USER |
+          base::FILE_PERMISSION_READ_BY_GROUP |
+          base::FILE_PERMISSION_READ_BY_OTHERS))
     return FILE_ERROR_FAILED;
 
   mounted_files_.insert(id);