Flutter engine in native world registers _flutter.listViews extension on the VM. App registers extensions on the VM as well, and clients such as dart-code that are connected to flutter daemon call those extensions. Flutter daemon calls _flutter.listViews before proceeding to call methods registered by the app.

The web engine does not have information about the VM and its isolates so it cannot implement _flutter.listViews method that requires this information. For a short term solution, we are implementing _flutter.listViews directly in dwds, but it would be cleaner and less bug prone to implement a solution somewhere in flutter (in case that API changes, for example).

Possible solutions:

• sdk developer library can provide information about VM uri so flutter web engine can connect to it and
  retrieve isolate information and implement _flutter.listView
• dwds can provide a hook to register service extensions directly on the chrome proxy service.