Add |RTCUIApplicationStatusObserver sharedInstance| call in ios test AppDelegate.

webrtc/test/ios/test_support.mm

 /*
  *  Copyright 2017 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.
  */
 
 #import <UIKit/UIKit.h>
 
 #include "webrtc/test/ios/test_support.h"
 
+#import "webrtc/sdk/objc/Framework/Classes/Common/RTCUIApplicationStatusObserver.h"
+
 // Springboard will kill any iOS app that fails to check in after launch within
 // a given time. Starting a UIApplication before invoking TestSuite::Run
 // prevents this from happening.
 
 // InitIOSRunHook saves the TestSuite and argc/argv, then invoking
 // RunTestsFromIOSApp calls UIApplicationMain(), providing an application
 // delegate class: WebRtcUnitTestDelegate. The delegate implements
 // application:didFinishLaunchingWithOptions: to invoke the TestSuite's Run
 // method.
 
@@ skipping 28 matching lines @@
   // Add a label with the app name.
   UILabel *label = [[UILabel alloc] initWithFrame:bounds];
   label.text = [[NSProcessInfo processInfo] processName];
   label.textAlignment = NSTextAlignmentCenter;
   [_window addSubview:label];
 
   // An NSInternalInconsistencyException is thrown if the app doesn't have a
   // root view controller. Set an empty one here.
   [_window setRootViewController:[[UIViewController alloc] init]];
 
+  // We want to call `RTCUIApplicationStatusObserver sharedInstance` as early as
+  // possible in the application lifecycle to set observation properly.
+  __unused RTCUIApplicationStatusObserver *observer =
+      [RTCUIApplicationStatusObserver sharedInstance];
+
   // Queue up the test run.
   [self performSelector:@selector(runTests) withObject:nil afterDelay:0.1];
   return YES;
 }
 
 - (void)runTests {
   int exitStatus = g_test_suite();
 
   // If a test app is too fast, it will exit before Instruments has has a
   // a chance to initialize and no test results will be seen.
@@ skipping 19 matching lines @@
   g_argv = argv;
 }
 
 void RunTestsFromIOSApp() {
   @autoreleasepool {
     exit(UIApplicationMain(g_argc, g_argv, nil, @"WebRtcUnitTestDelegate"));
   }
 }
 }  // namespace test
 }  // namespace rtc