Make MediaFileUtil run on thread pool.

webkit/fileapi/file_system_task_runners.h

Index: webkit/fileapi/file_system_task_runners.h
diff --git a/webkit/fileapi/file_system_task_runners.h b/webkit/fileapi/file_system_task_runners.h
new file mode 100644
index 0000000000000000000000000000000000000000..219e2af621ba841b4ef4ba5cb8166de4c3abf7ce
--- /dev/null
+++ b/webkit/fileapi/file_system_task_runners.h
@@ -0,0 +1,53 @@
+// 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 WEBKIT_FILEAPI_FILE_SYSTEM_TASK_RUNNERS_H_
+#define WEBKIT_FILEAPI_FILE_SYSTEM_TASK_RUNNERS_H_
+
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "webkit/fileapi/fileapi_export.h"
+
+namespace base {
+class SequencedTaskRunner;
+class SingleThreadTaskRunner;
+}  // namespace
+
+namespace fileapi {
+
+// This class holds task runners used for filesystem related stuff.
+class FILEAPI_EXPORT FileSystemTaskRunners {
+ public:
+  FileSystemTaskRunners(
+      base::SingleThreadTaskRunner* io_task_runner,
+      base::SingleThreadTaskRunner* file_task_runner,
+      base::SequencedTaskRunner* media_task_runner);
+
+  ~FileSystemTaskRunners();
+
+  static scoped_ptr<FileSystemTaskRunners> CreateMockTaskRunners();
+
+  base::SingleThreadTaskRunner* io_task_runner() {
+    return io_task_runner_.get();
+  }
+
+  base::SingleThreadTaskRunner* file_task_runner() {
+    return file_task_runner_.get();
+  }
+
+  base::SequencedTaskRunner* media_task_runner() {
+    return media_task_runner_.get();
+  }
+
+ private:
+  scoped_refptr<base::SingleThreadTaskRunner> io_task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> file_task_runner_;
+  scoped_refptr<base::SequencedTaskRunner> media_task_runner_;
+
+  DISALLOW_COPY_AND_ASSIGN(FileSystemTaskRunners);
+};
+
+}  // namespace fileapi
+
+#endif  // WEBKIT_FILEAPI_FILE_SYSTEM_TASK_RUNNERS_H_