Update iOS AppRTCDemo to use level controller.

NOTRY=True
BUG=

Review-Url: https://codereview.webrtc.org/2294913003
Cr-Commit-Position: refs/heads/master@{#13977}
diff --git a/webrtc/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.h b/webrtc/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.h
index ffffd12..3ca2dc2 100644
--- a/webrtc/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.h
+++ b/webrtc/examples/objc/AppRTCDemo/ios/ARDVideoCallViewController.h
@@ -25,6 +25,7 @@
                  isLoopback:(BOOL)isLoopback
                 isAudioOnly:(BOOL)isAudioOnly
           shouldMakeAecDump:(BOOL)shouldMakeAecDump
+      shouldUseLevelControl:(BOOL)shouldUseLevelControl
                    delegate:(id<ARDVideoCallViewControllerDelegate>)delegate;
 
 @end