WindowServer: Show PID and window ID in title bars for now.

This is useful for debugging since I'm often wondering which process some
window belongs to (and what the window ID is.)

WindowServer/WSWindow.cpp

@@ -7,6 +7,7 @@
 WSWindow::WSWindow(Process& process, int window_id)
     : m_process(process)
     , m_window_id(window_id)
+    , m_pid(process.pid())
 {
     WSWindowManager::the().add_window(*this);
 }