Cookies are set by libsoup and we are notifying about the handshake being sent before the cookie header is added to the request.
Created attachment 409776 [details] Patch
Comment on attachment 409776 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=409776&action=review > Source/WebKit/NetworkProcess/soup/WebSocketTaskSoup.cpp:83 > + g_signal_connect(msg, "starting", G_CALLBACK(+[](SoupMessage* msg, WebSocketTask* task) { +[] to convert to vanilla function pointer so we can use it in a signal callback is amazing... I didn't know this was possible!
Committed r267655: <https://trac.webkit.org/changeset/267655>