Enable injection of a custom NetEqFactory into PeerConnectionFactory.

Injecting both a custom NetEqFactory and an AudioDecoderFactory is not
supported, in that case the AudioDecoderFactory should be wrapped inside
the NetEqFactory.

Bug: webrtc:11005
Change-Id: I4e311eb1bfa03c91bca587d70540e81829f881c9
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158720
Commit-Queue: Ivo Creusen <ivoc@webrtc.org>
Reviewed-by: Karl Wiberg <kwiberg@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#29673}
diff --git a/api/peer_connection_interface.h b/api/peer_connection_interface.h
index 55cc593..7567ab1 100644
--- a/api/peer_connection_interface.h
+++ b/api/peer_connection_interface.h
@@ -85,6 +85,7 @@
 #include "api/fec_controller.h"
 #include "api/jsep.h"
 #include "api/media_stream_interface.h"
+#include "api/neteq/neteq_factory.h"
 #include "api/network_state_predictor.h"
 #include "api/packet_socket_factory.h"
 #include "api/rtc_error.h"
@@ -1318,6 +1319,7 @@
       network_state_predictor_factory;
   std::unique_ptr<NetworkControllerFactoryInterface> network_controller_factory;
   std::unique_ptr<MediaTransportFactory> media_transport_factory;
+  std::unique_ptr<NetEqFactory> neteq_factory;
 };
 
 // PeerConnectionFactoryInterface is the factory interface used for creating