Edited by amirh:

This is a request for a communication mechanism between the Flutter app's Dart code, and Javascript code running in the WebView.

Original description:
Android allows specifying a Javascript interface to act as a bridge between the webview and Android code. Similarly, iOS provides the UiWebView stringByEvaluatingJavaScriptFromString method that allows communicating with the underlying webview. Flutter should support this.

Example use case: Embedding a rich text HTML editor to edit existing HTML.