libservo: Introduce SiteDataManager and NetworkManager

[janvarga]

This PR introduces an initial SiteDataManager abstraction intended
primarily for embedders to inspect and manage site data.

At this stage, SiteDataManager supports clearing network cache and
cookies. Cookie related functionality has been moved here from the
former CookieManager, which has been renamed to NetworkManager to
better reflect its scope.

Additional site data APIs will be added in follow-up PRs.

Testing: Added a new integration test with a TODO comment.

[mrobinson]

Just a question: does it makes sense for the CookieManager to become a NetworkManager data structure or to combine it into the SiteDataManager. I'm starting to be convinced that cookies are also site data as well. What do you think?

Would you be willing to combine the two data structures into a single SiteDataManager?

[janvarga]

Just a question: does it makes sense for the CookieManager to become a NetworkManager data structure or to combine it into the SiteDataManager. I'm starting to be convinced that cookies are also site data as well. What do you think?

Would you be willing to combine the two data structures into a single SiteDataManager?

Yeah, now that I think about it again, it probably makes more sense to have just one manager. I was likely too influenced by WPE WebKit. That said, the planned protocol handlers probably do deserve a separate NetworkManager.

How about a new follow-up PR where I rename CookieManager to NetworkManager and move clear_cookies to SiteDataManager?

[janvarga]

How about a new follow-up PR where I rename CookieManager to NetworkManager and move clear_cookies to SiteDataManager?

I can also do that in this PR, if that's preferred.

[mrobinson]

I can also do that in this PR, if that's preferred.

Maybe it would indeed be better to do it all in one go here to avoid code churn. I think you could also combine the cookie.rs test into the new test file as well.

Thanks!

[janvarga]

Ok, added a new commit for that.

[mrobinson]

Looks good!

One nit to address before landing:

Let's name the Rust files after the data structure they expose, so site_data.rs would be site_data_manager.rs and net.rs would be network_manager.rs. This is just to be consistent with the API Rust files we already have.

[janvarga]

Let's name the Rust files after the data structure they expose, so site_data.rs would be site_data_manager.rs and net.rs would be network_manager.rs. This is just to be consistent with the API Rust files we already have.

Done (in a new commit)