Add missing exports from the platform interface

Author: rekire

packages/webview_flutter/webview_flutter/lib/src/webview_controller.dart

@@ -370,6 +370,30 @@ class WebViewController {
     return platform.setOnConsoleMessage(onConsoleMessage);
   }
 
+  /// Sets a callback that notifies the host application that the web page
+  /// wants to display a JavaScript alert() dialog.
+  Future<void> setOnJavaScriptAlertDialog(
+      Future<void> Function(JavaScriptAlertDialogRequest request)
+      onJavaScriptAlertDialog) async {
+    return platform.setOnJavaScriptAlertDialog(onJavaScriptAlertDialog);
+  }
+
+  /// Sets a callback that notifies the host application that the web page
+  /// wants to display a JavaScript confirm() dialog.
+  Future<void> setOnJavaScriptConfirmDialog(
+      Future<bool> Function(JavaScriptConfirmDialogRequest request)
+      onJavaScriptConfirmDialog) async {
+    return platform.setOnJavaScriptConfirmDialog(onJavaScriptConfirmDialog);
+  }
+
+  /// Sets a callback that notifies the host application that the web page
+  /// wants to display a JavaScript prompt() dialog.
+  Future<void> setOnJavaScriptTextInputDialog(
+      Future<String> Function(JavaScriptTextInputDialogRequest request)
+      onJavaScriptTextInputDialog) async {
+    return platform.setOnJavaScriptTextInputDialog(onJavaScriptTextInputDialog);
+  }
+
   /// Gets the value used for the HTTP `User-Agent:` request header.
   Future<String?> getUserAgent() {
     return platform.getUserAgent();

packages/webview_flutter/webview_flutter/lib/webview_flutter.dart

@@ -4,10 +4,13 @@
 
 export 'package:webview_flutter_platform_interface/webview_flutter_platform_interface.dart'
     show
+        JavaScriptAlertDialogRequest,
+        JavaScriptConfirmDialogRequest,
         JavaScriptConsoleMessage,
         JavaScriptLogLevel,
         JavaScriptMessage,
         JavaScriptMode,
+        JavaScriptTextInputDialogRequest,
         LoadRequestMethod,
         NavigationDecision,
         NavigationRequest,