Revert of Storing raw audio sink for default audio track.

webrtc/audio/audio_sink.h

Index: webrtc/audio/audio_sink.h
diff --git a/webrtc/audio/audio_sink.h b/webrtc/audio/audio_sink.h
index 205bb7f4abf16827dc8d35c934208b7bf5414b14..d022b32855daf553482437db9a9dd87c56df163c 100644
--- a/webrtc/audio/audio_sink.h
+++ b/webrtc/audio/audio_sink.h
@@ -19,12 +19,10 @@
 #include <inttypes.h>
 #include <stddef.h>
 
-#include "webrtc/base/refcount.h"
-
 namespace webrtc {
 
 // Represents a simple push audio sink.
-class AudioSinkInterface : public rtc::RefCountInterface {
+class AudioSinkInterface {
  public:
   virtual ~AudioSinkInterface() {}