feat: extract visibleViewController in UIApplication extension and use it

ios/Classes/InAppBrowser/InAppBrowserManager.swift

@@ -98,27 +98,6 @@ public class InAppBrowserManager: ChannelDelegate {
         presentViewController(webViewController: webViewController)
     }
     
-    
-    private func visibleViewController() -> UIViewController? {
-        guard let rootViewController =  UIApplication.shared.keyWindow?.rootViewController else {
-            return nil
-        }
-        return getVisibleViewController(rootViewController)
-    }
-
-    private func getVisibleViewController(_ rootViewController: UIViewController) -> UIViewController? {
-        if let presentedViewController = rootViewController.presentedViewController {
-            return getVisibleViewController(presentedViewController)
-        }
-        if let navigationController = rootViewController as? UINavigationController {
-            return navigationController.visibleViewController
-        }
-        if let tabBarController = rootViewController as? UITabBarController {
-            return tabBarController.selectedViewController
-        }
-        return rootViewController
-    }
-    
     public func presentViewController(webViewController: InAppBrowserWebViewController) {
         let storyboard = UIStoryboard(name: InAppBrowserManager.WEBVIEW_STORYBOARD, bundle: Bundle(for: InAppWebViewFlutterPlugin.self))
         let navController = storyboard.instantiateViewController(withIdentifier: InAppBrowserManager.NAV_STORYBOARD_CONTROLLER_ID) as! InAppBrowserNavigationController
@@ -131,7 +110,7 @@ public class InAppBrowserManager: ChannelDelegate {
             animated = false
         }
         
-        guard let visibleViewController = visibleViewController() else {
+        guard let visibleViewController = UIApplication.shared.visibleViewController else {
             assertionFailure("Failure inet the visibleViewController!")
             return
         }

ios/Classes/SafariViewController/ChromeSafariBrowserManager.swift

@@ -90,7 +90,7 @@ public class ChromeSafariBrowserManager: ChannelDelegate {
         
         if #available(iOS 9.0, *), let plugin = plugin {
             
-            if let flutterViewController = UIApplication.shared.delegate?.window.unsafelyUnwrapped?.rootViewController {
+            if let flutterViewController = UIApplication.shared.visibleViewController {
                 // flutterViewController could be casted to FlutterViewController if needed
                 
                 let safariSettings = SafariBrowserSettings()

ios/Classes/UIApplication+VisibleViewController.swift

@@ -0,0 +1,31 @@
+//
+//  UIApplication+VisibleViewController.swift
+//  flutter_inappwebview
+//
+//  Created by Alexandru Terente on 02.08.2023.
+//
+
+import UIKit
+
+extension UIApplication {
+
+    var visibleViewController: UIViewController? {
+        guard let rootViewController = keyWindow?.rootViewController else {
+            return nil
+        }
+        return getVisibleViewController(rootViewController)
+    }
+
+    private func getVisibleViewController(_ rootViewController: UIViewController) -> UIViewController? {
+        if let presentedViewController = rootViewController.presentedViewController {
+            return getVisibleViewController(presentedViewController)
+        }
+        if let navigationController = rootViewController as? UINavigationController {
+            return navigationController.visibleViewController
+        }
+        if let tabBarController = rootViewController as? UITabBarController {
+            return tabBarController.selectedViewController
+        }
+        return rootViewController
+    }
+}