servo: Merge #7141 - Update rust-layers to get 2d transform + clipping support (from glennw:2d-clipping-update); r=pcwalton

Source-Repo: https://github.com/servo/servo
Source-Revision: 5af93e9ca3500a75f845614f17323d258ee72d71

servo/components/msg/compositor_msg.rs

@@ -55,8 +55,8 @@ impl LayerId {
 
 #[derive(Clone, Copy, Debug, PartialEq)]
 pub enum LayerKind {
-    Layer2D,
-    Layer3D,
+    NoTransform,
+    HasTransform,
 }
 
 /// The scrolling policy of a layer.