When moving from the C API, we need SPI to get the WKWebProcessPlugInFrame from a JSContext and a securityOrigin property.
<rdar://problem/69336928>
Created attachment 409331 [details] Patch
Committed r267387: <https://trac.webkit.org/changeset/267387> All reviewed patches have been landed. Closing bug and clearing flags on attachment 409331 [details].
Please add new API tests for new API and SPI being added.