Disable on localhosts

[ablanathtanalba]

This fixes #817

Instead of disabling pb entirely on localhosts, this now just removes learning capabilities when the tab origin is from a predictable localhost address.

[ghostwords]

I think it would be better to take the tack discussed in #817 (comment) and disable learning on local domains. This means Privacy Badger will still be enabled and will report domains, do widget replacement, etc.. We just don't want to ever get local domains in snitch_map, you know?

[ghostwords]

So that's for when the site you are on is a local host domain.

What about when local host domains are included as resources on a site?

• If it's a local host site with local host resources, we should make sure Privacy Badger treats local host resources as first party on local host sites.
• If it's a non-local site with local host resources ... This is a weird one. No need to specially handle this case at this time, I think. We can revisit later if necessary.

Edit: We currently completely ignore local host domains when it comes to modifying/blocking their requests and reporting them in the UI. I don't think we have a similar check on the learning side, however.

[ablanathtanalba]

I think it would be better to take the tack discussed in #817 (comment) and disable learning on local domains. This means Privacy Badger will still be enabled and will report domains, do widget replacement, etc.. We just don't want to ever get local domains in snitch_map, you know?

Ah, this makes sense! I'll go this route, then. Next commit will go this direction 👍

[ghostwords]

There are other learning code paths: review the places incognito.learningEnabled() gets called.

[ghostwords]

Now that #2679 was merged, this should be rebased on master.