Introduce media::RendererFactory interface.

media/base/renderer_factory.h

+// Copyright 2014 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_RENDERER_FACTORY_H_
+#define MEDIA_BASE_RENDERER_FACTORY_H_
+
+#include "base/macros.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/media_export.h"
+#include "media/base/renderer.h"
+
+namespace base {
+class SingleThreadTaskRunner;
+}
+
+namespace media {
+
+class AudioRendererSink;
+
+// A factory class for creating media::Renderer to be used by media pipeline.
+class MEDIA_EXPORT RendererFactory {
+ public:
+  RendererFactory();
+  virtual ~RendererFactory();
+
+  // Creates and returns a Renderer. All methods of the created Renderer except
+  // for GetMediaTime() will be called on the |media_task_runner|.
+  // GetMediaTime() could be called on any thread.
+  // The created Renderer can use the |audio_renderer_sink| to render audio.
+  virtual scoped_ptr<Renderer> CreateRenderer(
+      const scoped_refptr<base::SingleThreadTaskRunner>& media_task_runner,
+      AudioRendererSink* audio_renderer_sink) = 0;
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(RendererFactory);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_RENDERER_FACTORY_H_