Provide isAudioEnabled flag to control audio unit.

webrtc/examples/objc/AppRTCDemo/ios/ARDMainView.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 ARDMainView;
 
 @protocol ARDMainViewDelegate <NSObject>
 
 - (void)mainView:(ARDMainView *)mainView
-             didInputRoom:(NSString *)room
-               isLoopback:(BOOL)isLoopback
-              isAudioOnly:(BOOL)isAudioOnly
-   shouldDelayAudioConfig:(BOOL)shouldDelayAudioConfig;
+      didInputRoom:(NSString *)room
+        isLoopback:(BOOL)isLoopback
+       isAudioOnly:(BOOL)isAudioOnly
+    useManualAudio:(BOOL)useManualAudio;
 
 - (void)mainViewDidToggleAudioLoop:(ARDMainView *)mainView;
 
 @end
 
 // The main view of AppRTCDemo. It contains an input field for entering a room
 // name on apprtc to connect to.
 @interface ARDMainView : UIView
 
 @property(nonatomic, weak) id<ARDMainViewDelegate> delegate;
 // Updates the audio loop button as needed.
 @property(nonatomic, assign) BOOL isAudioLoopPlaying;
 
 @end