Bug 52153

This test in CachedResourceLoader::determineRevalidationPolicy() // Avoid loading the same resource multiple times for a single document, even if the cache policies would tell us to. if (m_validatedURLs.contains(existingResource->url())) return Use; means that we never revalidate a resource for a given document (except if it has Cache-control:no-store which is handled separately), no matter how expired it is. While we don't want to load a resource multiple times during a page load we should probably allow revalidation for resources that are requested by a script after the page load has completed. This might be achieved simply be clearing (and not adding to it afterwards) m_validatedURLs when the page load completes. It would also be good to figure out what exactly other browsers do here before making any changes.