Move AudioRenderer out of Filter heirarchy.

media/base/callback_util.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 MEDIA_BASE_CALLBACK_UTIL_H_
+#define MEDIA_BASE_CALLBACK_UTIL_H_
+
+#include <queue>
+
+#include "base/callback.h"
+#include "base/memory/scoped_ptr.h"
+
+namespace media {
+
+typedef base::Callback<void(const base::Closure&)> ClosureCB;
+
+// Executes the closures in FIFO order, executing |done_cb| when the last
+// closure has completed running.
+//
+// |done_cb| will be executed on the same thread as the last completed closure
+// or the current thread if |closures| is empty.
+void RunInSeries(scoped_ptr<std::queue<ClosureCB> > closures,
+                 const base::Closure& done_cb);
+
+// Executes the closures in parallel, executing |done_cb| when all closures have
+// completed running.
+//
+// No attempt is made to parallelize execution of the closures. In other words,
+// this method will run all closures in FIFO order if said closures execute
+// synchronously on the same call stack.
+//
+// |done_cb| will be executed on the same thread as the last completed closure
+// or the current thread if |closures| is empty.
+void RunInParallel(scoped_ptr<std::queue<ClosureCB> > closures,
+                   const base::Closure& done_cb);
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_CALLBACK_UTIL_H_