Update all site scores to use Lighthouse 3.0 metrics

[addyosmani]

The majority of our current interactive scores are based on Lighthouse 1.0 rather than 2.0 released at Google I/O. It broke down Time-to-Interactive into the firstInteractive and consistentlyInteractive metrics.

Moving forward, I propose we continue to keep our 'Interactive' buckets, but use the firstInteractive score as it's pretty close to what we've been using so far. We can make a call on when/if we want to shift to consistentlyInteractive once that metric has had more time to mature 👴 👵

What does this mean for new apps that we're getting PR'd in?

The current WebPageTest integration with Lighthouse uses 2.0, however we know that there are issues with it failing to capture TTI correctly for our HN apps, like GoogleChrome/lighthouse#2394. I think we should wait until it's more stable in that regard before switching all the results listed on the site over to using it. Does that make sense?

Does this mean we're going to block any new apps from landing?

Nah. If anything, as long as they're correctly getting interactivity scores reported in Lighthouse 2.0 over on WPT they should be fine. We'll just want to make sure that folks are using the firstInteractive definition so we're as close to consistent as possible.

Let's review how far along Lighthouse 2.0 is in July.

cc @kristoferbaxter @housseindjirdeh

[housseindjirdeh]

Sounds good, once those issues capturing TTI are resolved I'll be happy to rerun tests for all the implementations and use the First Interactive times. We can then decide to use consistentlyInteractive once we feel it's smoothed out 💃

[addyosmani]

@kristoferbaxter Thanks so much for getting this kickstarted off this weekend 🎉

[housseindjirdeh]

Opening up discussion on this again 💬

@addyosmani how do you feel about the consistentlyInteractive metrics with the current LH version (2.3.0)? My experiences with it have usually shown it to match the firstInteractive numbers, but wanted to check in too see if it has smoothed out to a point we can start shifting to it 🙌

[housseindjirdeh]

As discussed, we'll be holding off adding this for a few more days until WPT lands LH 3.0 🚀