Update iOS AppRTCDemo to use level controller.

webrtc/examples/objc/AppRTCDemo/ARDAppClient.h

Index: webrtc/examples/objc/AppRTCDemo/ARDAppClient.h
diff --git a/webrtc/examples/objc/AppRTCDemo/ARDAppClient.h b/webrtc/examples/objc/AppRTCDemo/ARDAppClient.h
index 95e20d46a9d95340da0b5fac14a4878f06f6a602..2186abe6936fee7241fca537d33020d4f2ea002c 100644
--- a/webrtc/examples/objc/AppRTCDemo/ARDAppClient.h
+++ b/webrtc/examples/objc/AppRTCDemo/ARDAppClient.h
@@ -65,10 +65,13 @@ typedef NS_ENUM(NSInteger, ARDAppClientState) {
 // If |isLoopback| is true, the call will connect to itself.
 // If |isAudioOnly| is true, video will be disabled for the call.
 // If |shouldMakeAecDump| is true, an aecdump will be created for the call.
+// If |shouldUseLevelControl| is true, the level controller will be used
+// in the call.
 - (void)connectToRoomWithId:(NSString *)roomId
                  isLoopback:(BOOL)isLoopback
                 isAudioOnly:(BOOL)isAudioOnly
-          shouldMakeAecDump:(BOOL)shouldMakeAecDump;
+          shouldMakeAecDump:(BOOL)shouldMakeAecDump
+      shouldUseLevelControl:(BOOL)shouldUseLevelControl;
 
 // Disconnects from the AppRTC servers and any connected clients.
 - (void)disconnect;