Delete AudioOutputMixer.

media/audio/audio_util.h

Index: media/audio/audio_util.h
diff --git a/media/audio/audio_util.h b/media/audio/audio_util.h
index 18cda41788b4e777b882fc5439221f565d368907..6067b21db3f2b66ba8ce6780c8829800c0e183e5 100644
--- a/media/audio/audio_util.h
+++ b/media/audio/audio_util.h
@@ -39,15 +39,6 @@ MEDIA_EXPORT bool AdjustVolume(void* buf,
                                int bytes_per_sample,
                                float volume);
 
-// MixStreams() mixes 2 audio streams with same sample rate and number of
-// samples, adjusting volume on one of them.
-// Dst += Src * volume.
-MEDIA_EXPORT void MixStreams(void* dst,
-                             void* src,
-                             size_t buflen,
-                             int bytes_per_sample,
-                             float volume);
-
 // Returns the default audio output hardware sample-rate.
 MEDIA_EXPORT int GetAudioHardwareSampleRate();