Update iOS AppRTCDemo to use the updated Objective-C API.

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 c1a0376564f18bfa33527a3d6ab725863628f3b6..3fd218c2fd83d657ad8b41d3ab24b5c2d1958f29 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
+++ b/webrtc/examples/objc/AppRTCDemo/ARDAppClient+Internal.h
@@ -10,17 +10,16 @@
 
 #import "ARDAppClient.h"
 
+#import "webrtc/api/objc/RTCPeerConnection.h"
+
 #import "ARDRoomServerClient.h"
 #import "ARDSignalingChannel.h"
 #import "ARDTURNClient.h"
-#import "RTCPeerConnection.h"
-#import "RTCPeerConnectionDelegate.h"
-#import "RTCPeerConnectionFactory.h"
-#import "RTCSessionDescriptionDelegate.h"
-#import "RTCStatsDelegate.h"
+
+@class RTCPeerConnectionFactory;
 
 @interface ARDAppClient () <ARDSignalingChannelDelegate,
-  RTCPeerConnectionDelegate, RTCSessionDescriptionDelegate, RTCStatsDelegate>
+  RTCPeerConnectionDelegate>
 
 // All properties should only be mutated from the main queue.
 @property(nonatomic, strong) id<ARDRoomServerClient> roomServerClient;