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/LibWebView/CMakeLists.txt

@@ -8,6 +8,7 @@ set(SOURCES
     InspectorClient.cpp
     RequestServerAdapter.cpp
     SearchEngine.cpp
+    SocketPair.cpp
     SourceHighlighter.cpp
     URL.cpp
     UserAgent.cpp