Revert of Revert of Chromecast: Play audio streams not supported by CMA via default renderer

chromecast/media/base/switching_media_renderer.h

+// Copyright 2015 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 CHROMECAST_MEDIA_BASE_SWITCHING_MEDIA_RENDERER_H_
+#define CHROMECAST_MEDIA_BASE_SWITCHING_MEDIA_RENDERER_H_
+
+#include "base/macros.h"
+#include "base/memory/scoped_ptr.h"
+#include "media/base/renderer.h"
+
+namespace media {
+class DemuxerStreamProvider;
+}
+
+namespace chromecast {
+namespace media {
+
+// Chromecast's custom media renderer which is capable of selecting an
+// appropriate media renderer at runtime depending on the content.
+// We'll look at media types of media streams present in DemuxerStreamProvider
+// and will use either CMA-based renderer (for media types that are supported by
+// our hardware decoder - H264 and VP8 video, AAC and Vorbis audio) or the
+// default Chrome media renderer (this will allow us to support audio codecs
+// like FLAC and Opus, which are decoded in software).
+class SwitchingMediaRenderer : public ::media::Renderer {
+ public:
+  SwitchingMediaRenderer(
+      scoped_ptr<::media::Renderer> default_renderer,
+      scoped_ptr<::media::Renderer> cma_renderer);
+  ~SwitchingMediaRenderer() override;
+
+  // ::media::Renderer implementation:
+  void Initialize(
+      ::media::DemuxerStreamProvider* demuxer_stream_provider,
+      const base::Closure& init_cb,
+      const ::media::StatisticsCB& statistics_cb,
+      const ::media::BufferingStateCB& buffering_state_cb,
+      const ::media::Renderer::PaintCB& paint_cb,
+      const base::Closure& ended_cb,
+      const ::media::PipelineStatusCB& error_cb) override;
+  void SetCdm(::media::CdmContext* cdm_context,
+              const ::media::CdmAttachedCB& cdm_attached_cb) override;
+  void Flush(const base::Closure& flush_cb) override;
+  void StartPlayingFrom(base::TimeDelta time) override;
+  void SetPlaybackRate(float playback_rate) override;
+  void SetVolume(float volume) override;
+  base::TimeDelta GetMediaTime() override;
+  bool HasAudio() override;
+  bool HasVideo() override;
+
+ private:
+  // Returns the pointer to the actual renderer being used
+  ::media::Renderer* GetRenderer() const;
+
+  ::media::DemuxerStreamProvider* demuxer_stream_provider_;
+  scoped_ptr<::media::Renderer> default_renderer_;
+  scoped_ptr<::media::Renderer> cma_renderer_;
+
+  DISALLOW_COPY_AND_ASSIGN(SwitchingMediaRenderer);
+};
+
+}  // namespace media
+}  // namespace chromecast
+
+#endif  // CHROMECAST_MEDIA_BASE_SWITCHING_MEDIA_RENDERER_H_