Provide isAudioEnabled flag to control audio unit.

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 16 matching lines @@
 @end
 
 @implementation ARDVideoCallViewController {
   ARDAppClient *_client;
   RTCVideoTrack *_remoteVideoTrack;
   RTCVideoTrack *_localVideoTrack;
   AVAudioSessionPortOverride _portOverride;
 }
 
 @synthesize videoCallView = _videoCallView;
+@synthesize delegate = _delegate;
 
 - (instancetype)initForRoom:(NSString *)room
                  isLoopback:(BOOL)isLoopback
-                isAudioOnly:(BOOL)isAudioOnly {
+                isAudioOnly:(BOOL)isAudioOnly
+                   delegate:(id<ARDVideoCallViewControllerDelegate>)delegate {
   if (self = [super init]) {
+    _delegate = delegate;
     _client = [[ARDAppClient alloc] initWithDelegate:self];
     [_client connectToRoomWithId:room
                       isLoopback:isLoopback
                      isAudioOnly:isAudioOnly];
   }
   return self;
 }
 
 - (void)loadView {
   _videoCallView = [[ARDVideoCallView alloc] initWithFrame:CGRectZero];
@@ skipping 118 matching lines @@
   _remoteVideoTrack = nil;
   [_videoCallView.remoteVideoView renderFrame:nil];
   _remoteVideoTrack = remoteVideoTrack;
   [_remoteVideoTrack addRenderer:_videoCallView.remoteVideoView];
 }
 
 - (void)hangup {
   self.remoteVideoTrack = nil;
   self.localVideoTrack = nil;
   [_client disconnect];
-  if (![self isBeingDismissed]) {
-    [self.presentingViewController dismissViewControllerAnimated:YES
-                                                      completion:nil];
-  }
+  [_delegate viewControllerDidFinish:self];
 }
 
 - (void)switchCamera {
   RTCVideoSource* source = self.localVideoTrack.source;
   if ([source isKindOfClass:[RTCAVFoundationVideoSource class]]) {
     RTCAVFoundationVideoSource* avSource = (RTCAVFoundationVideoSource*)source;
     avSource.useBackCamera = !avSource.useBackCamera;
   }
 }
 
@@ skipping 15 matching lines @@
 - (void)showAlertWithMessage:(NSString*)message {
   UIAlertView* alertView = [[UIAlertView alloc] initWithTitle:nil
                                                       message:message
                                                      delegate:nil
                                             cancelButtonTitle:@"OK"
                                             otherButtonTitles:nil];
   [alertView show];
 }
 
 @end