Motown: Define MediaRenderer and make it the way we identify renderers.

services/media/audio/audio_track_impl.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 SERVICES_MEDIA_AUDIO_AUDIO_TRACK_IMPL_H_
 #define SERVICES_MEDIA_AUDIO_AUDIO_TRACK_IMPL_H_
 
 #include <deque>
 #include <set>
 
 #include "base/synchronization/lock.h"
 #include "mojo/public/cpp/bindings/binding.h"
 #include "mojo/public/cpp/bindings/callback.h"
 #include "mojo/services/media/audio/interfaces/audio_track.mojom.h"
 #include "mojo/services/media/common/cpp/linear_transform.h"
+#include "mojo/services/media/core/interfaces/media_renderer.mojom.h"
 #include "services/media/audio/audio_pipe.h"
 #include "services/media/audio/fwd_decls.h"
 #include "services/media/common/timeline_control_site.h"
 
 namespace mojo {
 namespace media {
 namespace audio {
 
-class AudioTrackImpl : public AudioTrack {
+class AudioTrackImpl : public AudioTrack, public MediaRenderer {
  public:
   // TODO(johngro): Find a better place for this constant.  It affects the
   // behavior of more than just the Audio Track implementation.
   static constexpr size_t PTS_FRACTIONAL_BITS = 12;
 
   ~AudioTrackImpl() override;
-  static AudioTrackImplPtr Create(InterfaceRequest<AudioTrack> iface,
-                                  AudioServerImpl* owner);
+  static AudioTrackImplPtr Create(
+      InterfaceRequest<AudioTrack> track_request,
+      InterfaceRequest<MediaRenderer> renderer_request,
+      AudioServerImpl* owner);
 
   // Shutdown the audio track, unlinking it from all outputs, closing
   // connections to all clients and removing it from its owner server's list.
   void Shutdown();
 
   // Methods used by the output manager to link this track to different outputs.
   void AddOutput(AudioTrackToOutputLinkPtr link);
   void RemoveOutput(AudioTrackToOutputLinkPtr link);
 
   // Accessors used by AudioOutputs during mixing to access parameters which are
   // important for the mixing process.
   void SnapshotRateTrans(LinearTransform* out, uint32_t* generation = nullptr);
 
   const LinearTransform::Ratio& FractionalFrameToMediaTimeRatio() const {
     return frame_to_media_ratio_;
   }
 
   uint32_t BytesPerFrame() const { return bytes_per_frame_; }
   const AudioMediaTypeDetailsPtr& Format() const { return format_; }
   float DbGain() const { return db_gain_; }
 
  private:
   friend class AudioPipe;
 
-  AudioTrackImpl(InterfaceRequest<AudioTrack> track,
+  AudioTrackImpl(InterfaceRequest<AudioTrack> track_request,
+                 InterfaceRequest<MediaRenderer> renderer_request,
                  AudioServerImpl* owner);
 
   // Implementation of AudioTrack interface.
-  void Describe(const DescribeCallback& cbk) override;
-  void Configure(AudioTrackConfigurationPtr configuration,
-                 InterfaceRequest<MediaConsumer> req) override;
-  void GetTimelineControlSite(InterfaceRequest<MediaTimelineControlSite> req)
-      override;
   void SetGain(float db_gain) override;
 
+  // MediaRenderer implementation.
+  void GetSupportedMediaTypes(
+      const GetSupportedMediaTypesCallback& callback) override;
+  void SetMediaType(MediaTypePtr media_type) override;
+  void GetConsumer(InterfaceRequest<MediaConsumer> consumer_request) override;
+  void GetTimelineControlSite(
+      InterfaceRequest<MediaTimelineControlSite> control_site_request) override;
+
   // Methods called by our AudioPipe.
   //
   // TODO(johngro): MI is banned by style, but multiple interface inheritance
   // (inheriting for one or more base classes consisting only of pure virtual
   // methods) is allowed.  Consider defining an interface for AudioPipe
   // encapsulation so that AudioPipe does not have to know that we are an
   // AudioTrackImpl (just that we implement its interface).
   void OnPacketReceived(AudioPipe::AudioPacketRefPtr packet);
   bool OnFlushRequested(const MediaConsumer::FlushCallback& cbk);
 
   AudioTrackImplWeakPtr     weak_this_;
   AudioServerImpl*          owner_;
-  Binding<AudioTrack>       binding_;
+  Binding<AudioTrack>       track_binding_;
+  Binding<MediaRenderer>    renderer_binding_;
   AudioPipe                 pipe_;
   TimelineControlSite       timeline_control_site_;
   TimelineRate              frames_per_ns_;
   LinearTransform::Ratio    frame_to_media_ratio_;
   uint32_t                  bytes_per_frame_ = 1;
   AudioMediaTypeDetailsPtr  format_;
   AudioTrackToOutputLinkSet outputs_;
   float                     db_gain_ = 0.0;
 };
 
 }  // namespace audio
 }  // namespace media
 }  // namespace mojo
 
 #endif  // SERVICES_MEDIA_AUDIO_AUDIO_TRACK_IMPL_H_