* LoadData: Use regular load but intercept request
The method we used before, `createBrowserWithHtml`, is implemented by
KCEF. This method creates a `file://` url and adds handlers for that.
Instead, use regular `createBrowser` and intercept the request later on.
This has the effect of creating the page with the correct origin, while
still setting the requested HTML instead of live data. This is important
for scripts due to CORS.
Also fixes a mistake in the ResourceRequestHandler, where (a) the status
was not set, resulting in ABORT, (b) the return value of `readResponse`
was correct (`false` too early) and (c) the callback was unnecessarily
called on the MainLoop.
Based on https://stackoverflow.com/a/52423252/
* Convince the compiler we're doing it right
Invoking "public final" methods would fail. Not sure why this only
happens for some extensions, but it does. We need to tell the compiler
we're sure we have access to it, for some reason...
* JS: Invoke result handler on the loop
Some extensions call WebView methods on the result, so this should be on
the same loop as the WebView itself
* JS: Await arguments
* Fix using wrong URL property for errors
Constantin Piber
0b021e6c42