Interacting with OEM components like WebView is something that is possible today, but not as smooth as path as we'd like.
Specifically displaying web or video content inline with Flutter content are tracked by:
Flutter content displays inside a FlutterView, which is itself a normal UIView or android.View and can be inserted into a normal iOS or Android view hierarchy. So you can already just use a normal WebView or UIMovieView/android.VideoView next to or on top of a FlutterView today by writing some Objective-C/Swift or Java code in your Apps.
There is an example of putting other views next to a FlutterView in:
as well as communicating with those views and other Objective-C or Java code via our HostMessages interface.
This is something we're actively working on improving.