Provide isAudioEnabled flag to control audio unit.

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

 /*
  *  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.
  */
 
 #import <UIKit/UIKit.h>
 
+@class ARDVideoCallViewController;
+@protocol ARDVideoCallViewControllerDelegate <NSObject>
+
+- (void)viewControllerDidFinish:(ARDVideoCallViewController *)viewController;
+
+@end
+
 @interface ARDVideoCallViewController : UIViewController
 
+@property(nonatomic, weak) id<ARDVideoCallViewControllerDelegate> delegate;
+
 - (instancetype)initForRoom:(NSString *)room
                  isLoopback:(BOOL)isLoopback
-                isAudioOnly:(BOOL)isAudioOnly;
+                isAudioOnly:(BOOL)isAudioOnly
+                   delegate:(id<ARDVideoCallViewControllerDelegate>)delegate;
 
 @end