Use of plugins in WebView

[Philipp Dörfler]

How impossible would be the use of plugins such as the Adobe Acrobat Reader
or the Mac OS X embedded PDF preview in Safari for WebView? Does the
embedded WebKit engine include an implementation of that plugin API or has
that been omitted?

Also: How hard would it be to embed the respective platform's native
browser oneself? Can I obtain a handle for a JFX panel that I can then give
to WinAPI? How much would that interfere with the compositing and rendering
done by prism?
Being able to obtain a handle would (in my naive view) theoretically allow
to include another OpenGL context in an JFX app. Albeit I'm afraid that
prism wouldn't be happy about this either.