arc: Add utility functions to implement ARC content file system

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 {
+

[hidehiko, 2016/11/04 17:19:49]

Unnecessary empty line?

[hashimoto, 2016/11/07 05:34:16]

Done.

+namespace intent_helper_util {
+
+// Utility to call IntentHelperInstance::GetFileSize on the IO thread.

[hidehiko, 2016/11/04 17:19:49]

The comment looks ambiguous.
1) This function is called on IO thread.
2) GetFileSize is called on IO thread.
IIUC, former, right? Could you disambiguate? Ditto for below.

[hashimoto, 2016/11/07 05:34:16]

Done.

[hidehiko, 2016/11/07 18:07:54]

Much clearer to me!

+void GetFileSizeOnIOThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::GetFileSizeCallback& callback);
+
+// Utility to call IntentHelperInstance::OpenFileToRead on the IO thread.
+void OpenFileToReadOnIOThread(
+    const GURL& arc_url,
+    const mojom::IntentHelperInstance::OpenFileToReadCallback& callback);
+
+}  // namespace intent_helper_util
+

[hidehiko, 2016/11/04 17:19:49]

Ditto.

[hashimoto, 2016/11/07 05:34:16]

Done.

+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_INTENT_HELPER_UTIL_H_