arc: Empty implementation of ARC content file system

chrome/browser/chromeos/arc/fileapi/arc_content_file_system_file_stream_reader.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_ARC_CONTENT_FILE_SYSTEM_FILE_STREAM_READER_H_
+#define CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_CONTENT_FILE_SYSTEM_FILE_STREAM_READER_H_
+
+#include "storage/browser/fileapi/file_stream_reader.h"
+
+namespace arc {
+
+class ArcContentFileSystemFileStreamReader : public storage::FileStreamReader {
+ public:
+  ArcContentFileSystemFileStreamReader(const storage::FileSystemURL& url,
+                                       int64_t offset,
+                                       int64_t max_bytes_to_read);
+  ~ArcContentFileSystemFileStreamReader() override;
+
+  // storage::FileStreamReader override:
+  int Read(net::IOBuffer* buffer,
+           int buffer_length,
+           const net::CompletionCallback& callback) override;
+  int64_t GetLength(const net::Int64CompletionCallback& callback) override;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(ArcContentFileSystemFileStreamReader);
+};
+
+}  // namespace arc
+
+#endif  // CHROME_BROWSER_CHROMEOS_ARC_FILEAPI_ARC_CONTENT_FILE_SYSTEM_FILE_STREAM_READER_H_