Possible to register sw at diff scope using headers

[ahmed1490]

Perhaps this could open up other ways of screwing up.

• Multi-author sites w3c/ServiceWorker#468 (comment)
• https://developer.mozilla.org/en-US/docs/Web/API/Service_Worker_API/Using_Service_Workers

quote: If your server worker is active on a client being served with the Service-Worker-Allowed header, you can specify a list of max scopes for that worker.

This means.. if diff clients are serving sw's in a distributed system (for eg: sites like tumblr or jsbin - which may allow users to create sw at some point) - they have more ways of screwing up root sw. (completely unregistering the root sw).