Allow mocking SendSideCongestionController for Call tests.

webrtc/modules/congestion_controller/include/congestion_controller.h

Index: webrtc/modules/congestion_controller/include/congestion_controller.h
diff --git a/webrtc/modules/congestion_controller/include/congestion_controller.h b/webrtc/modules/congestion_controller/include/congestion_controller.h
index 0e69047b9a7f7ce2b06316a0650f3dcce79e9f91..1249170cc48fc13cf2ec13998a9c251cbb029d78 100644
--- a/webrtc/modules/congestion_controller/include/congestion_controller.h
+++ b/webrtc/modules/congestion_controller/include/congestion_controller.h
@@ -50,19 +50,19 @@ class CongestionController : public CallStatsObserver,
   using Observer = SendSideCongestionController::Observer;
 
   CongestionController(const Clock* clock,
-                       Observer* observer,
+                       Observer* /* observer */,

[nisse-webrtc, 2017/04/26 07:37:14]

I think it's best to keep this argument. We plan to delete this all-in-one class
fairly soon, in favor of the receive side and send side classes, but it's kept
for now to not break downstream projects. 

[Zach Stein, 2017/04/26 20:39:53]

What downstream projects might this break? I'm not seeing anything worrying in
code search, but I might not be looking in the right places. Or perhaps this is
more public than I am assuming?

                        RemoteBitrateObserver* /* remote_bitrate_observer */,
                        RtcEventLog* event_log,
                        PacketRouter* packet_router)
-      : send_side_cc_(clock, observer, event_log, packet_router),
+      : send_side_cc_(clock, event_log, packet_router),
         receive_side_cc_(clock, packet_router) {}
   CongestionController(const Clock* clock,
-                       Observer* observer,
-                       RemoteBitrateObserver* remote_bitrate_observer,
+                       Observer* /* observer */,
+                       RemoteBitrateObserver* /* remote_bitrate_observer */,
                        RtcEventLog* event_log,
                        PacketRouter* packet_router,
                        std::unique_ptr<PacedSender> pacer)
-      : send_side_cc_(clock, observer, event_log, std::move(pacer)),
+      : send_side_cc_(clock, event_log, std::move(pacer)),
         receive_side_cc_(clock, packet_router) {}
 
   virtual ~CongestionController() {}