[fsp] Separate logic for saving/restoring state to a separate class.

chrome/browser/chromeos/file_system_provider/provided_file_system_info.h

 // Copyright 2014 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_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INFO_H_
 #define CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INFO_H_
 
 #include <string>
 
 #include "base/files/file_path.h"
 
 namespace chromeos {
 namespace file_system_provider {
 
 // Options for creating the provided file system info.
 struct MountOptions {
   MountOptions();
 
   // Only mandatory fields.
   MountOptions(const std::string& file_system_id,
                const std::string& display_name);
 
-  std::string extension_id;
   std::string file_system_id;
   std::string display_name;
   bool writable;
   bool supports_notify_tag;
 };
 
 // Contains information about the provided file system instance.
 class ProvidedFileSystemInfo {
  public:
   ProvidedFileSystemInfo();
@@ skipping 28 matching lines @@
   bool supports_notify_tag_;
 
   // Mount path of the underlying file system.
   base::FilePath mount_path_;
 };
 
 }  // namespace file_system_provider
 }  // namespace chromeos
 
 #endif  // CHROME_BROWSER_CHROMEOS_FILE_SYSTEM_PROVIDER_PROVIDED_FILE_SYSTEM_INFO_H_