content::RTCRtpSenders/Receivers using track adapter references.

content/renderer/media/webrtc/rtc_rtp_receiver.h

Index: content/renderer/media/webrtc/rtc_rtp_receiver.h
diff --git a/content/renderer/media/webrtc/rtc_rtp_receiver.h b/content/renderer/media/webrtc/rtc_rtp_receiver.h
index 5990976f490336f7b9766b0330374790c08b4b61..9427029147f41c17978e9cc4a96b857d74986beb 100644
--- a/content/renderer/media/webrtc/rtc_rtp_receiver.h
+++ b/content/renderer/media/webrtc/rtc_rtp_receiver.h
@@ -8,6 +8,7 @@
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "content/common/content_export.h"
+#include "content/renderer/media/webrtc/webrtc_media_stream_track_adapter_map.h"
 #include "third_party/WebKit/public/platform/WebMediaStreamTrack.h"
 #include "third_party/WebKit/public/platform/WebRTCRtpReceiver.h"
 #include "third_party/webrtc/api/rtpreceiverinterface.h"
@@ -23,7 +24,8 @@ class CONTENT_EXPORT RTCRtpReceiver : public blink::WebRTCRtpReceiver {
       const webrtc::RtpReceiverInterface* webrtc_rtp_receiver);
 
   RTCRtpReceiver(webrtc::RtpReceiverInterface* webrtc_rtp_receiver,

[Guido Urdaneta, 2017/06/19 16:10:51]

Update raw pointer to scoped_refptr by value.

According to
https://groups.google.com/a/chromium.org/forum/#!topic/chromium-dev/TlL1D-Djt...

the consensus on passing scoped_refptr to a function that takes ownership is to
pass it by value and then call std::move() internally to avoid the additional
AddRef.

[hbos_chromium, 2017/06/19 16:45:39]

I've never seen std::move be used in combination with scoped_refptr in our
codebase, and I think moving can be misleading since ownership is still shared,
but I've seen const scoped_refptr<>& all over the place. I'll do that?

[Guido Urdaneta, 2017/06/20 11:26:15]

Pass by value, not const-ref

-                 const blink::WebMediaStreamTrack& web_track);
+                 std::unique_ptr<WebRtcMediaStreamTrackAdapterMap::AdapterRef>
+                     track_adapter);
   ~RTCRtpReceiver() override;
 
   uintptr_t Id() const override;
@@ -35,7 +37,10 @@ class CONTENT_EXPORT RTCRtpReceiver : public blink::WebRTCRtpReceiver {
 
  private:
   const scoped_refptr<webrtc::RtpReceiverInterface> webrtc_rtp_receiver_;
-  const blink::WebMediaStreamTrack web_track_;
+  // The track adapter is the glue between blink and webrtc layer tracks.
+  // Keeping a reference to the adapter ensures it is not disposed, as is
+  // required as long as the webrtc layer track is in use by the receiver.
+  std::unique_ptr<WebRtcMediaStreamTrackAdapterMap::AdapterRef> track_adapter_;
 
   DISALLOW_COPY_AND_ASSIGN(RTCRtpReceiver);
 };