Run the C++ generated component through the GL backend

... which in turn forward to the corelib, but with the GL renderer attached.

sixtyfps_runtime/corelib/lib.rs

@@ -1,3 +1,5 @@
+use core::ptr::NonNull;
+
 pub mod graphics;
 
 pub mod abi {
@@ -57,6 +59,31 @@ where
     }
 }
 
+pub fn run_component<GraphicsBackend, GraphicsFactoryFunc>(
+    component_type: *const abi::datastructures::ComponentType,
+    component: NonNull<abi::datastructures::ComponentImpl>,
+    graphics_backend_factory: GraphicsFactoryFunc,
+) where
+    GraphicsBackend: graphics::GraphicsBackend + 'static,
+    GraphicsFactoryFunc:
+        FnOnce(&winit::event_loop::EventLoop<()>, winit::window::WindowBuilder) -> GraphicsBackend,
+{
+    let component = unsafe {
+        abi::datastructures::ComponentUniquePtr::new(
+            NonNull::new_unchecked(component_type as *mut _),
+            component,
+        )
+    };
+
+    let main_window = MainWindow::new(graphics_backend_factory);
+
+    main_window.run_event_loop(move |_width, _height, mut _renderer| {
+        component.visit_items(|item| {
+            println!("Rendering... {:?}", item.rendering_info());
+        });
+    });
+}
+
 #[cfg(test)]
 mod tests {
     #[test]