Draft new layout API

wgpu/src/renderer.rs

@@ -423,7 +423,7 @@ impl Debugger for Renderer {
     fn explain<Message>(
         &mut self,
         widget: &dyn Widget<Message, Self>,
-        layout: Layout<'_>,
+        layout: &Layout,
         cursor_position: Point,
         color: Color,
     ) -> Self::Output {
@@ -438,7 +438,7 @@ impl Debugger for Renderer {
 }
 
 fn explain_layout(
-    layout: Layout,
+    layout: &Layout,
     color: Color,
     primitives: &mut Vec<Primitive>,
 ) {