Soft Update seems way to aggressive

Soft Update is basically just an Update as specified here [1]. The description states "The user agent may call this as often as it likes to check for updates.", which seems fine.

My issue is that the "Handle Fetch" section [2] mandates that we call Soft Update when a load is intercepted, if:
a) It a non-subresource load
or
b) if it is a subresource load and 24 hours have past since last update check

I think a) is way too aggressive. Basically, every intercepted navigation will cause Update to be called. Also, because the default value for updateViaCache is "imports", by default, every update is going to go to the network.

Also note that this behavior is tested by update-after-navigation-fetch-event.https.html WPT test.

I think we should apply the 24 hour limiting to all resource loads, not only subresource ones.

[1] https://w3c.github.io/ServiceWorker/#soft-update-algorithm
[2] https://w3c.github.io/ServiceWorker/#on-fetch-request-algorithm (Steps 20, 21 & 22)

Start with the Soft Update and Handle Fetch sections linked in the issue, then run the WPT test update-after-navigation-fetch-event.https.html to understand the current behavior. A complete change would require agreement on applying the 24-hour limit to navigation loads and updating the specification and affected test expectations.