Christian Uldall Pedersen

I have been experimenting with this PR for a few days, and run into the issue that the created doesn't have the `credentialless` attribute set, and so won't load if...

> Otherwise the current solution for all browsers is that the hosted webapp has the `Cross-Origin-Embedder-Policy: credentialless` header set. In most cases people don't own the sites that they iframe,...

It seems that on other platforms these kind of platform specific parameters are set on the `WebViewControllerCreationParams` implementation. An example from the [Webkit impl](https://github.com/ThomasAunvik/flutter-packages/blob/0870dc84d364aad79fba7a57ef2984b01b073c4d/packages/webview_flutter/webview_flutter_wkwebview/lib/src/webkit_webview_controller.dart#L52). Here some boolean parameters like `allowsInlineMediaPlayback`...

I managed to test the credentialless branch just now, and it works as expected and the contents of the iframe is loaded: 

I have been testing the PR quite a bit, and created this issue because Godot games being loaded in the iframe resulted in an error: https://github.com/flutter/flutter/issues/150119 However since then I...

@slavap I do not believe PWA's require a service worker nowadays. See [https://web.dev/articles/install-criteria#criteria](https://web.dev/articles/install-criteria#criteria).