Merge branch 'master' into beacon

core/src/renderer.rs

@@ -106,7 +106,19 @@ impl Default for Style {
 /// a window nor a compositor.
 pub trait Headless {
     /// Creates a new [`Headless`] renderer;
-    fn new(default_font: Font, default_text_size: Pixels) -> Self;
+    fn new(
+        default_font: Font,
+        default_text_size: Pixels,
+        backend: Option<&str>,
+    ) -> impl Future<Output = Option<Self>>
+    where
+        Self: Sized;
+
+    /// Returns the unique name of the renderer.
+    ///
+    /// This name may be used by testing libraries to uniquely identify
+    /// snapshots.
+    fn name(&self) -> String;
 
     /// Draws offscreen into a screenshot, returning a collection of
     /// bytes representing the rendered pixels in RGBA order.