Navigation inside webview with atos payment system

First, thank you very much for this very nice plugin for flutter.

Next, i need your help because i am trying to implement payment system inside flutter_webview_plugin.

When i open the webview for example like this :

```
// close any open browser (happen on hot reload)
await flutterWebviewPlugin.close();
_isOpen = true;

// init server
_server = await _createServer();
_listenCode(_server);

// catch onDestroy event of WebView
flutterWebviewPlugin.onDestroy.first.then((_) {
_close();
});

flutterWebviewPlugin.onBackPressed.first.then((_) {
_close();
});

// launch url inside webview
flutterWebviewPlugin.launch(url,
clearCookies: !cookie, fullScreen: fullscreen);
```

It is working well and my user is redirect to flutter webview to my payment page.
But when i am on the payment page atos ask me to chose my credit card like this :


On the computer when i click on a card everything is working well and i am redirected to the next page but when i am inside the flutter webview nothing happened and the flutter console show :

```
D/AppTracker(13525): App Event: stop
I/zygote (13525): Do partial code cache collection, code=123KB, data=113KB
I/zygote (13525): After code cache collection, code=123KB, data=113KB
I/zygote (13525): Increasing code cache capacity to 512KB
E/BoostFramework(13525): BoostFramework() : Exception_1 = java.lang.NoSuchMethodException: perfIOPrefetchStart [int, class java.lang.String]
E/BoostFramework(13525): BoostFramework() : Exception_1 = java.lang.NoSuchMethodException: perfIOPrefetchStart [int, class java.lang.String]
D/AppTracker(13525): App Event: start
I/chromium(13525): [INFO:CONSOLE(0)] "The SSL certificate used to load resources from https://sandbox-webkit.lemonway.fr will be distrusted in the future. Once distrusted, users will be prevented from loading these resources. See https://g.co/chrome/symantecpkicerts for more information.", source: (0)
I/chromium(13525): [INFO:CONSOLE(0)] "The SSL certificate used to load resources from https://sandbox-webkit.lemonway.fr will be distrusted in the future. Once distrusted, users will be prevented from loading these resources. See https://g.co/chrome/symantecpkicerts for more information.", source: https://sandbox-webkit.lemonway.fr/myapp/dev/?moneyInToken=123456789101112131415&lang=fr (0)
```

Do you have any ideas please ?

Begin by reproducing the card-selection flow from the flutterWebviewPlugin.launch(url, clearCookies:, fullScreen:) call and inspect the Android WebView console output shown in the report. Done means the Atos payment page accepts the card selection and navigates to the next page inside the plugin; the issue does not name a source file or test to update.

由索引模型根据 Issue 内容生成。