drive: Stop using /dev/null to store an empty file to the cache from CreateFileOperation

chrome/browser/chromeos/drive/file_system_util.h

 // Copyright (c) 2012 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 CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_UTIL_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_UTIL_H_
 
 #include <string>
 
 #include "base/callback_forward.h"
@@ skipping 24 matching lines @@
 // The extension for dirty files. The file names look like
 // "<resource-id>.local".
 const base::FilePath::CharType kLocallyModifiedFileExtension[] =
     FILE_PATH_LITERAL("local");
 // The extension for mounted files. The file names look like
 // "<resource-id>.<md5>.mounted".
 const base::FilePath::CharType kMountedArchiveFileExtension[] =
     FILE_PATH_LITERAL("mounted");
 const base::FilePath::CharType kWildCard[] =
     FILE_PATH_LITERAL("*");
-// The path is used for creating a symlink in "pinned" directory for a file
-// which is not yet fetched.
-const base::FilePath::CharType kSymLinkToDevNull[] =
-    FILE_PATH_LITERAL("/dev/null");
 
 // Special resource IDs introduced to manage pseudo directory tree locally.
 // These strings are supposed to be different from any resource ID used on the
 // server, and are never sent to the server. Practical resource IDs used so far
 // have only alphabets/numbers ([a-zA-Z0-9]) and ':'.
 // Hence '<' and '>' around the directory name have been added to make them
 // different from normal server-side IDs.
 const char kDriveGrandRootSpecialResourceId[] = "<drive>";
 
 const char kDriveOtherDirSpecialResourceId[] = "<other>";
@@ skipping 175 matching lines @@
 // Reads URL from a GDoc file.
 GURL ReadUrlFromGDocFile(const base::FilePath& file_path);
 
 // Reads resource ID from a GDoc file.
 std::string ReadResourceIdFromGDocFile(const base::FilePath& file_path);
 
 }  // namespace util
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_FILE_SYSTEM_UTIL_H_