Add stats overlay to iOS AppRTCDemo.

webrtc/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.m

 /*
  *  Copyright 2015 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 70 matching lines @@
   self.localVideoTrack = localVideoTrack;
 }
 
 - (void)appClient:(ARDAppClient *)client
     didReceiveRemoteVideoTrack:(RTCVideoTrack *)remoteVideoTrack {
   self.remoteVideoTrack = remoteVideoTrack;
   _videoCallView.statusLabel.hidden = YES;
 }
 
 - (void)appClient:(ARDAppClient *)client
+      didGetStats:(NSArray *)stats {
+  _videoCallView.statsView.stats = stats;
+  [_videoCallView setNeedsLayout];
+}
+
+- (void)appClient:(ARDAppClient *)client
          didError:(NSError *)error {
   NSString *message =
       [NSString stringWithFormat:@"%@", error.localizedDescription];
   [self showAlertWithMessage:message];
   [self hangup];
 }
 
 #pragma mark - ARDVideoCallViewDelegate
 
 - (void)videoCallViewDidHangup:(ARDVideoCallView *)view {
   [self hangup];
 }
 
 - (void)videoCallViewDidSwitchCamera:(ARDVideoCallView *)view {
   // TODO(tkchin): Rate limit this so you can't tap continously on it.
   // Probably through an animation.
   [self switchCamera];
 }
 
+- (void)videoCallViewDidEnableStats:(ARDVideoCallView *)view {
+  _client.shouldGetStats = YES;
+  _videoCallView.statsView.hidden = NO;
+}
+
 #pragma mark - Private
 
 - (void)setLocalVideoTrack:(RTCVideoTrack *)localVideoTrack {
   if (_localVideoTrack == localVideoTrack) {
     return;
   }
   [_localVideoTrack removeRenderer:_videoCallView.localVideoView];
   _localVideoTrack = nil;
   [_videoCallView.localVideoView renderFrame:nil];
   _localVideoTrack = localVideoTrack;
@@ skipping 48 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end