Switch browser/extensions/api/file_system/file_system_api.[h|cc] to the TaskScheduler API

chrome/browser/extensions/api/file_system/file_system_api.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_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 #define CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_
 
 #include <memory>
 #include <string>
 #include <vector>
@@ skipping 182 matching lines @@
  public:
   DECLARE_EXTENSION_FUNCTION("fileSystem.getWritableEntry",
                              FILESYSTEM_GETWRITABLEENTRY)
 
  protected:
   ~FileSystemGetWritableEntryFunction() override {}
   bool RunAsync() override;
 
  private:
   void CheckPermissionAndSendResponse();
-  void SetIsDirectoryOnFileThread();
+  void SetIsDirectoryAsync();
 
   // The path to the file for which a writable entry has been requested.
   base::FilePath path_;
 };
 
 class FileSystemIsWritableEntryFunction : public UIThreadExtensionFunction {
  public:
   DECLARE_EXTENSION_FUNCTION("fileSystem.isWritableEntry",
                              FILESYSTEM_ISWRITABLEENTRY)
 
@@ skipping 198 matching lines @@
   ExtensionFunction::ResponseAction Run() override;
 
  private:
   ChromeExtensionFunctionDetails chrome_details_;
 };
 #endif
 
 }  // namespace extensions
 
 #endif  // CHROME_BROWSER_EXTENSIONS_API_FILE_SYSTEM_FILE_SYSTEM_API_H_