[webview_flutter_wkwebview] Implements currentUrl (#5974)

Author: bparrishMines

packages/webview_flutter/webview_flutter_wkwebview/lib/src/web_kit_webview_widget.dart

@@ -354,6 +354,9 @@ class WebKitWebViewPlatformController extends WebViewPlatformController {
   @override
   Future<String?> getTitle() => webView.getTitle();
 
+  @override
+  Future<String?> currentUrl() => webView.getUrl();
+
   @override
   Future<void> scrollTo(int x, int y) async {
     webView.scrollView.setContentOffset(Point<double>(

packages/webview_flutter/webview_flutter_wkwebview/test/src/web_kit_webview_widget_test.dart

@@ -783,6 +783,14 @@ void main() {
         expect(testController.getTitle(), completion('Web Title'));
       });
 
+      testWidgets('currentUrl', (WidgetTester tester) async {
+        await buildWidget(tester);
+
+        when(mockWebView.getUrl())
+            .thenAnswer((_) => Future<String>.value('myUrl.com'));
+        expect(testController.currentUrl(), completion('myUrl.com'));
+      });
+
       testWidgets('scrollTo', (WidgetTester tester) async {
         await buildWidget(tester);