Some electron API can't be hidden

[miaulightouch]

some of web API is implemented in Electron way, not natively.
It shouldn't be considered an upstream issue, but it still a big problem because anyone would have ability to detect you're using electron or not.

ref: window-setup.js

[miaulightouch]

it seems a more safely fork here: brave/muon

but it would be VERY painful due to it's not well-documented.