Storing raw audio sink for default audio track.

talk/app/webrtc/mediastreamprovider.h

Index: talk/app/webrtc/mediastreamprovider.h
diff --git a/talk/app/webrtc/mediastreamprovider.h b/talk/app/webrtc/mediastreamprovider.h
index 585d51bcc8178c1ba245a40f6121cbe1971d5671..ba87cb34b51675c008bc389be1d2bbaffa6b87ba 100644
--- a/talk/app/webrtc/mediastreamprovider.h
+++ b/talk/app/webrtc/mediastreamprovider.h
@@ -29,7 +29,7 @@
 #define TALK_APP_WEBRTC_MEDIASTREAMPROVIDER_H_
 
 #include "webrtc/base/basictypes.h"
-#include "webrtc/base/scoped_ptr.h"
+#include "webrtc/base/scoped_ref_ptr.h"
 
 namespace cricket {
 
@@ -75,7 +75,7 @@ class AudioProviderInterface {
   // passed to the provider.
   virtual void SetRawAudioSink(
       uint32_t ssrc,
-      rtc::scoped_ptr<webrtc::AudioSinkInterface> sink) = 0;
+      rtc::scoped_refptr<webrtc::AudioSinkInterface> sink) = 0;

[the sun, 2016/01/08 13:14:26]

Assuming we'll be replacing this with shared_ptr once we can use that, is it
then still a good idea to pass by value? scoped_refptr just contains one
pointer, but shared_ptr has at least two. Should we pass by const & instead?

[Taylor Brandstetter, 2016/01/08 19:46:58]

const & would indeed save some unnecessary copying; this is just the pattern I
was used to seeing.

[the sun, 2016/01/11 10:38:27]

For scoped_ptr (and current scoped_ref_ptr) it won't matter since they just
contain a single pointer; the compiler is pretty smart. :) Thanks for updating
though!

[tommi, 2016/01/12 08:58:06]

Passing scoped_refptr by value will trigger an extra pair of AddRef/Release
calls which can mean unnecessary interlocked operations. That + virtual calls,
so should be passed by const ref.  Thanks for catching Fredrik.

 
  protected:
   virtual ~AudioProviderInterface() {}