Fix plugin resolution on Linux
Fix plugin resolution on Linux

Summary:
Linux appears to spawn a completely separate browser process whereas MacOS either
forks or uses a thread. Either way, Linux no longer has access to the parent
process's environment variables we use to look up plugins. Using
the remote module fixes that.

In the medium term, we should convert the `plugin` module to not rely on import effects
and instead use the IPC mechanism, making the plugin resolution asynchronous:

https://electronjs.org/docs/api/web-contents#contentssendchannel-arg1-arg2-

That would also allow us to do the plugin resolution while starting up the browser window,
lowering the startup time.

Reviewed By: danielbuechele

Differential Revision: D9423628

fbshipit-source-id: 76351f267864147c4494aadaf4e16ea636952118

facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper,facebook/flipper