Fetching the stylesheets takes ~100ms on startup, on the critical path. Preloading the files knocks off that overhead.
Created attachment 651148 [details] [diff] [review]
Created attachment 651858 [details] [diff] [review]
Prefetch the "built-in" stylesheet cache in content processes
Sorry roc, not sure if there's anyone who knows both the stylesheet cache code and content-process startup. Let me know if I should ping someone else for review.