Add UINavigationController to AppRTCMobile.

webrtc/examples/objc/AppRTCMobile/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 13 matching lines @@
 #pragma mark - UIApplicationDelegate methods
 
 - (BOOL)application:(UIApplication *)application
     didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
   RTCInitFieldTrials(RTCFieldTrialOptionsSendSideBwe);
   RTCInitializeSSL();
   RTCSetupInternalTracer();
   _window =  [[UIWindow alloc] initWithFrame:[[UIScreen mainScreen] bounds]];
   [_window makeKeyAndVisible];
   ARDMainViewController *viewController = [[ARDMainViewController alloc] init];
-  _window.rootViewController = viewController;
+
+  UINavigationController *root =
+      [[UINavigationController alloc] initWithRootViewController:viewController];
+  root.navigationBar.translucent = NO;
+  _window.rootViewController = root;
 
 #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(RTCLoggingSeverityWarning);
 #endif
 
   return YES;
 }
 
 - (void)applicationWillTerminate:(UIApplication *)application {
   RTCShutdownInternalTracer();
   RTCCleanupSSL();
 }
 
 @end