From a sandbox perspective, define the WebContent process as launched in WebPage::create. This ensures that the sandbox state variable is set before any content is loaded, which is not immediately clear from doing it when the load is committed.
<rdar://problem/110648262>
Pull request: https://github.com/WebKit/WebKit/pull/14868
Committed 265080@main (b21d74bab849): <https://commits.webkit.org/265080@main> Reviewed commits have been landed. Closing PR #14868 and removing active labels.