Fixed missing clearHistory webview method implementation on Android, Fixed iOS...

Fixed missing clearHistory webview method implementation on Android, Fixed iOS crash when using CookieManager getCookies for an URL and the host URL is null

example/lib/in_app_webiew_example.screen.dart

@@ -123,7 +123,6 @@ class _InAppWebViewExampleScreenState extends State<InAppWebViewExampleScreen> {
                       return ShouldOverrideUrlLoadingAction.ALLOW;
                     },
                     onLoadStop: (InAppWebViewController controller, String url) async {
-                      print(CookieManager)
                       print("onLoadStop $url");
                       setState(() {
                         this.url = url;