Revert of Storing raw audio sink for default audio track.

talk/media/webrtc/fakewebrtccall.h

Index: talk/media/webrtc/fakewebrtccall.h
diff --git a/talk/media/webrtc/fakewebrtccall.h b/talk/media/webrtc/fakewebrtccall.h
index ca08c8ccac467aa4c7b037a262fcb3a3e5807c95..3528c7a7b1e1e12a2290e71a5e9f5660bd5707f9 100644
--- a/talk/media/webrtc/fakewebrtccall.h
+++ b/talk/media/webrtc/fakewebrtccall.h
@@ -89,9 +89,6 @@
   void SetStats(const webrtc::AudioReceiveStream::Stats& stats);
   int received_packets() const { return received_packets_; }
   void IncrementReceivedPackets();
-  const rtc::scoped_refptr<webrtc::AudioSinkInterface>& sink() const {
-    return sink_;
-  }
 
  private:
   // webrtc::ReceiveStream implementation.
@@ -109,13 +106,12 @@
 
   // webrtc::AudioReceiveStream implementation.
   webrtc::AudioReceiveStream::Stats GetStats() const override;
-  void SetSink(
-      const rtc::scoped_refptr<webrtc::AudioSinkInterface>& sink) override;
+  void SetSink(rtc::scoped_ptr<webrtc::AudioSinkInterface> sink) override;
 
   webrtc::AudioReceiveStream::Config config_;
   webrtc::AudioReceiveStream::Stats stats_;
   int received_packets_;
-  rtc::scoped_refptr<webrtc::AudioSinkInterface> sink_;
+  rtc::scoped_ptr<webrtc::AudioSinkInterface> sink_;
 };
 
 class FakeVideoSendStream final : public webrtc::VideoSendStream,