LibWeb+WebContent: Spawn Worker processes from the chrome

Instead of spawning these processes from the WebContent process, we now
create them in the Browser chrome.

Part 1/N of "all processes are owned by the chrome".

Userland/Libraries/LibWeb/Worker/WebWorkerClient.h

@@ -10,6 +10,7 @@
 #include <LibIPC/ConnectionToServer.h>
 #include <LibWeb/Worker/WebWorkerClientEndpoint.h>
 #include <LibWeb/Worker/WebWorkerServerEndpoint.h>
+#include <LibWebView/SocketPair.h>
 
 namespace Web::HTML {
 
@@ -21,6 +22,8 @@ class WebWorkerClient final
 public:
     explicit WebWorkerClient(NonnullOwnPtr<Core::LocalSocket>);
 
+    WebView::SocketPair dup_sockets();
+
 private:
     virtual void die() override;
 };