[Chromecast] Process streams with different post-processing.

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

Index: chromecast/media/cma/backend/alsa/audio_filter_factory.h
diff --git a/chromecast/media/cma/backend/alsa/audio_filter_factory.h b/chromecast/media/cma/backend/alsa/audio_filter_factory.h
index 5f8dcda132e3f14db24b70e367e6c7bf94b90499..cb91fbceb718514ed2324e357b2618508904824e 100644
--- a/chromecast/media/cma/backend/alsa/audio_filter_factory.h
+++ b/chromecast/media/cma/backend/alsa/audio_filter_factory.h
@@ -15,7 +15,12 @@ namespace media {
 class AudioFilterFactory {
  public:
   // FilterType specifies the usage of the created filter.
-  enum FilterType { PRE_LOOPBACK_FILTER, POST_LOOPBACK_FILTER };
+  enum FilterType {
+    MEDIA_AUDIO_FILTER = 0,
+    TTS_AUDIO_FILTER,
+    COMMUNICATION_AUDIO_FILTER,
+    ALARM_AUDIO_FILTER,
+  };
 
   // Creates a new AudioFilterInterface.
   static std::unique_ptr<AudioFilterInterface> MakeAudioFilter(