Start working on a Widgets library.

Widgets/EventLoop.h

@@ -0,0 +1,30 @@
+#pragma once
+
+#include <AK/OwnPtr.h>
+#include <AK/Vector.h>
+
+class Event;
+class Object;
+
+class EventLoop {
+public:
+    virtual ~EventLoop();
+
+    int exec();
+
+    virtual void waitForEvent() = 0;
+
+    void postEvent(Object* receiver, OwnPtr<Event>&&);
+
+    static EventLoop& main();
+
+protected:
+    EventLoop();
+
+private:
+    struct QueuedEvent {
+        Object* receiver { nullptr };
+        OwnPtr<Event> event;
+    };
+    Vector<QueuedEvent> m_queuedEvents;
+};