drive: Always use last_modified stored in ResourceEntry

chrome/browser/chromeos/drive/resource_entry_conversion.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_RESOURCE_ENTRY_CONVERSION_H_
 #define CHROME_BROWSER_CHROMEOS_DRIVE_RESOURCE_ENTRY_CONVERSION_H_
 
 #include <string>
 
 #include "base/files/file.h"
@@ skipping 21 matching lines @@
 // 2) Entries with multiple parents are allowed on drive.google.com. For these
 // entries, the first parent is chosen.
 bool ConvertToResourceEntry(const google_apis::ResourceEntry& input,
                             ResourceEntry* out_entry,
                             std::string* out_parent_resource_id);
 
 // Converts the resource entry to the platform file info.
 void ConvertResourceEntryToFileInfo(const ResourceEntry& entry,
                                     base::File::Info* file_info);
 
-// Converts the platform file info and sets it to the .file_info field of
-// the resource entry.
-void SetPlatformFileInfoToResourceEntry(const base::File::Info& file_info,
-                                        ResourceEntry* entry);
-
 }  // namespace drive
 
 #endif  // CHROME_BROWSER_CHROMEOS_DRIVE_RESOURCE_ENTRY_CONVERSION_H_