Add stats overlay to iOS AppRTCDemo.

webrtc/examples/objc/AppRTCDemo/ARDAppClient.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.
  */
 
@@ skipping 23 matching lines @@
 
 - (void)appClient:(ARDAppClient *)client
     didReceiveLocalVideoTrack:(RTCVideoTrack *)localVideoTrack;
 
 - (void)appClient:(ARDAppClient *)client
     didReceiveRemoteVideoTrack:(RTCVideoTrack *)remoteVideoTrack;
 
 - (void)appClient:(ARDAppClient *)client
          didError:(NSError *)error;
 
+- (void)appClient:(ARDAppClient *)client
+      didGetStats:(NSArray *)stats;
+
 @end
 
 // Handles connections to the AppRTC server for a given room. Methods on this
 // class should only be called from the main queue.
 @interface ARDAppClient : NSObject
 
+// If |shouldGetStats| is true, stats will be reported in 1s intervals through
+// the delegate.
+@property(nonatomic, assign) BOOL shouldGetStats;
 @property(nonatomic, readonly) ARDAppClientState state;
 @property(nonatomic, weak) id<ARDAppClientDelegate> delegate;
 
 // Convenience constructor since all expected use cases will need a delegate
 // in order to receive remote tracks.
 - (instancetype)initWithDelegate:(id<ARDAppClientDelegate>)delegate;
 
 // Establishes a connection with the AppRTC servers for the given room id.
 // TODO(tkchin): provide available keys/values for options. This will be used
 // for call configurations such as overriding server choice, specifying codecs
 // and so on.
 - (void)connectToRoomWithId:(NSString *)roomId
                     options:(NSDictionary *)options;
 
 // Disconnects from the AppRTC servers and any connected clients.
 - (void)disconnect;
 
 @end