Interacting with contents before they're set up.

[Kilian]

There is a sort of "race condition" between loading and webcontents being available:

• you want to set some settings before loading anything
• You can only set those settings on webcontents, which don't exist before you load something

I currently solve that with a load step of about:blank to instantiate the webContents, and only then setting what I need to set and loading whatever I want to load. Having either webcontents available or promise-able would really simplify the API + potentially speed up this process.