Add new view that renders local video using AVCaptureLayerPreview.

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 110 matching lines @@
   _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;
-  [_localVideoTrack addRenderer:_videoCallView.localVideoView];
+  RTCAVFoundationVideoSource *source = nil;
+  if ([localVideoTrack.source
+          isKindOfClass:[RTCAVFoundationVideoSource class]]) {
+    source = (RTCAVFoundationVideoSource*)localVideoTrack.source;
+  }
+  _videoCallView.localVideoView.captureSession = source.captureSession;
 }
 
 - (void)setRemoteVideoTrack:(RTCVideoTrack *)remoteVideoTrack {
   if (_remoteVideoTrack == remoteVideoTrack) {
     return;
   }
-  [_remoteVideoTrack removeRenderer:_videoCallView.localVideoView];
+  [_remoteVideoTrack removeRenderer:_videoCallView.remoteVideoView];
   _remoteVideoTrack = nil;
   [_videoCallView.remoteVideoView renderFrame:nil];
   _remoteVideoTrack = remoteVideoTrack;
   [_remoteVideoTrack addRenderer:_videoCallView.remoteVideoView];
 }
 
 - (void)hangup {
   self.remoteVideoTrack = nil;
   self.localVideoTrack = nil;
   [_client disconnect];
@@ skipping 31 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end