Use ArcFileSystemInstance to access files on ARC.

chrome/browser/chromeos/arc/fileapi/intent_helper_util.h

-// Copyright 2016 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_ARC_FILEAPI_INTENT_HELPER_UTIL_H_
-#define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_INTENT_HELPER_UTIL_H_
-
-#include "components/arc/common/intent_helper.mojom.h"
-#include "url/gurl.h"
-
-namespace arc {
-namespace intent_helper_util {
-
-using GetFileSizeCallback =
-    mojom::IntentHelperInstance::GetFileSizeDeprecatedCallback;
-using OpenFileToReadCallback =
-    mojom::IntentHelperInstance::OpenFileToReadDeprecatedCallback;
-
-// Utility which posts a task to run GetFileSize.
-// This function must be called on the IO thread.
-void GetFileSizeOnIOThread(const GURL& arc_url,
-                           const GetFileSizeCallback& callback);
-
-// Utility which posts a task to run OpenFileToRead.
-// This function must be called on the IO thread.
-void OpenFileToReadOnIOThread(const GURL& arc_url,
-                              const OpenFileToReadCallback& callback);
-
-}  // namespace intent_helper_util
-}  // namespace arc
-
-#endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_INTENT_HELPER_UTIL_H_