The fetch and process the linked resource steps for a preload link specify we should fire an error event when there's an error returned from the fetch.
<rdar://problem/101269688>
Pull request: https://github.com/WebKit/WebKit/pull/5473
I did such a poor job of explaining the issue and naming this bug. What we need to do is fire error events when a synchronous failure occurs. In particular, when we block the preload via CSP we don't ever schedule with the Network Process so the current code path for firing an error event never executes. Since we're supposed to return the spec's notion of a network error when we block due to CSP then we should also fire an error event when we block due to CSP.
Committed 255740@main (6bab27e2e35e): <https://commits.webkit.org/255740@main> Reviewed commits have been landed. Closing PR #5473 and removing active labels.