Erg, the idea of Google phoning home information about each page I visit at the browser level is a bit terrifying...
My idea doesn't require anything new except them measuring load times, which I'm guessing they're doing already for improving Chrome, and then using this data to influence search ranking. Everything else is already set up and working, and you opt into it if you're using Chrome and are logged in browser-wide.
https://bugs.chromium.org/p/chromium/issues/detail?id=432236