[Chromecast] Process streams with different post-processing.

chromecast/media/cma/backend/alsa/stream_mixer_alsa.h

Index: chromecast/media/cma/backend/alsa/stream_mixer_alsa.h
diff --git a/chromecast/media/cma/backend/alsa/stream_mixer_alsa.h b/chromecast/media/cma/backend/alsa/stream_mixer_alsa.h
index 53a48911f72ae92fe6fed42b1db7703d52aab2fd..2f28d56c41d2f669175c254ff13fbfabdbee1baf 100644
--- a/chromecast/media/cma/backend/alsa/stream_mixer_alsa.h
+++ b/chromecast/media/cma/backend/alsa/stream_mixer_alsa.h
@@ -28,6 +28,7 @@ class AudioBus;
 namespace chromecast {
 namespace media {
 class AlsaWrapper;
+class FilterGroup;
 
 // Mixer implementation. The mixer has one or more input queues; these can be
 // added/removed at any time. When an input source pushes frames to an input
@@ -67,6 +68,11 @@ class StreamMixerAlsa {
     // precedence for sample rates and will dictate when data is polled.
     virtual bool primary() const = 0;
 
+    // Returns a string describing the content type class.
+    // Should be from chromecast/media/base/audio_device_ids.h
+    // or media/audio/audio_device_description.h
+    virtual std::string name() const = 0;
+
     // Returns true if PrepareToDelete() has been called.
     virtual bool IsDeleting() const = 0;
 
@@ -195,10 +201,11 @@ class StreamMixerAlsa {
 
   void WriteFrames();
   bool TryWriteFrames();
-  void WriteMixedPcm(const ::media::AudioBus& mixed, int frames,
-      bool is_silence);
+  void WriteMixedPcm(std::vector<uint8_t>* interleaved, int frames);
   void UpdateRenderingDelay(int newly_pushed_frames);
+  size_t InterleavedSize(int frames);
   ssize_t BytesPerOutputFormatSample();
+  void ResizeBuffersIfNecessary(int chunk_size);
 
   static bool single_threaded_for_test_;
 
@@ -229,26 +236,15 @@ class StreamMixerAlsa {
   std::vector<std::unique_ptr<InputQueue>> inputs_;
   std::vector<std::unique_ptr<InputQueue>> ignored_inputs_;
   MediaPipelineBackendAlsa::RenderingDelay rendering_delay_;
-  // Buffer to write final interleaved data before sending to snd_pcm_writei().
-  std::vector<uint8_t> interleaved_;
-
-  // Buffers that hold audio data while it is mixed, before it is passed to the
-  // ALSA layer. These are kept as members of this class to minimize copies and
-  // allocations.
-  std::unique_ptr<::media::AudioBus> temp_;
-  std::unique_ptr<::media::AudioBus> mixed_;
 
   std::unique_ptr<base::Timer> retry_write_frames_timer_;
 
   int check_close_timeout_;
   std::unique_ptr<base::Timer> check_close_timer_;
 
+  std::vector<std::unique_ptr<FilterGroup>> filter_groups_;
   std::vector<CastMediaShlib::LoopbackAudioObserver*> loopback_observers_;
 
-  std::unique_ptr<AudioFilterInterface> pre_loopback_filter_;
-  std::unique_ptr<AudioFilterInterface> post_loopback_filter_;
-  int silence_frames_filtered_ = 0;
-
   DISALLOW_COPY_AND_ASSIGN(StreamMixerAlsa);
 };