Loopback mode for AppRTCDemo on iOS.

webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h

Index: webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
diff --git a/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h b/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
index 5a7b3878803762557469c17f22ef6c76170796b1..c1a0376564f18bfa33527a3d6ab725863628f3b6 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
+++ b/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
@@ -25,6 +25,7 @@
 // All properties should only be mutated from the main queue.
 @property(nonatomic, strong) id<ARDRoomServerClient> roomServerClient;
 @property(nonatomic, strong) id<ARDSignalingChannel> channel;
+@property(nonatomic, strong) id<ARDSignalingChannel> loopbackChannel;
 @property(nonatomic, strong) id<ARDTURNClient> turnClient;
 
 @property(nonatomic, strong) RTCPeerConnection *peerConnection;
@@ -41,6 +42,8 @@
 @property(nonatomic, strong) NSMutableArray *iceServers;
 @property(nonatomic, strong) NSURL *webSocketURL;
 @property(nonatomic, strong) NSURL *webSocketRestURL;
+@property(nonatomic, readonly) BOOL isLoopback;
+@property(nonatomic, readonly) BOOL isAudioOnly;
 
 @property(nonatomic, strong)
     RTCMediaConstraints *defaultPeerConnectionConstraints;