Add stats overlay to iOS AppRTCDemo.

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

 /*
  *  Copyright 2014 The WebRTC Project Authors. All rights reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #import "ARDAppClient.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"
 
 @interface ARDAppClient () <ARDSignalingChannelDelegate,
-    RTCPeerConnectionDelegate, RTCSessionDescriptionDelegate>
+  RTCPeerConnectionDelegate, RTCSessionDescriptionDelegate, RTCStatsDelegate>
 
 // 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<ARDTURNClient> turnClient;
 
 @property(nonatomic, strong) RTCPeerConnection *peerConnection;
 @property(nonatomic, strong) RTCPeerConnectionFactory *factory;
 @property(nonatomic, strong) NSMutableArray *messageQueue;
 
@@ skipping 10 matching lines @@
 
 @property(nonatomic, strong)
     RTCMediaConstraints *defaultPeerConnectionConstraints;
 
 - (instancetype)initWithRoomServerClient:(id<ARDRoomServerClient>)rsClient
                         signalingChannel:(id<ARDSignalingChannel>)channel
                               turnClient:(id<ARDTURNClient>)turnClient
                                 delegate:(id<ARDAppClientDelegate>)delegate;
 
 @end