This is a follow up of the regression in crbug.com/800750.

While investigating the perf regression introduced by landing OfflinePageModelTaskified, we found there are multiple clients calling Offline Pages to load databases.

The loading of the database should happen on demand, rather than at startup. There might be cases that the use case requires to load the DB on startup, but it should be confirmed. Otherwise it might be a good thing to redesign/refactor.

Probably list out the calling part, and create sub-tasks and use this one for tracking purposes.