Support delayed AudioUnit initialization.

webrtc/examples/objc/AppRTCDemo/ios/ARDAppDelegate.m

 /*
  *  Copyright 2013 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 25 matching lines @@
 #if defined(NDEBUG)
   // In debug builds the default level is LS_INFO and in non-debug builds it is
   // disabled. Continue to log to console in non-debug builds, but only
   // warnings and errors.
   RTCSetMinDebugLogLevel(kRTCLoggingSeverityWarning);
 #endif
 
   return YES;
 }
 
-- (void)applicationWillResignActive:(UIApplication *)application {
-  ARDMainViewController *viewController =
-      (ARDMainViewController *)_window.rootViewController;
-  [viewController applicationWillResignActive:application];
-}
-
 - (void)applicationWillTerminate:(UIApplication *)application {
   RTCShutdownInternalTracer();
   RTCCleanupSSL();
 }
 
 @end