Merge webxr repository (#35228)

Signed-off-by: Martin Robinson <mrobinson@igalia.com>

components/shared/webxr/space.rs

@@ -0,0 +1,28 @@
+use crate::InputId;
+use crate::Joint;
+use euclid::RigidTransform3D;
+
+#[derive(Clone, Copy, Debug)]
+#[cfg_attr(feature = "ipc", derive(serde::Serialize, serde::Deserialize))]
+/// A stand-in type for "the space isn't statically known since
+/// it comes from client side code"
+pub struct ApiSpace;
+
+#[derive(Clone, Copy, Debug, PartialEq)]
+#[cfg_attr(feature = "ipc", derive(serde::Serialize, serde::Deserialize))]
+pub enum BaseSpace {
+    Local,
+    Floor,
+    Viewer,
+    BoundedFloor,
+    TargetRay(InputId),
+    Grip(InputId),
+    Joint(InputId, Joint),
+}
+
+#[derive(Clone, Copy, Debug)]
+#[cfg_attr(feature = "ipc", derive(serde::Serialize, serde::Deserialize))]
+pub struct Space {
+    pub base: BaseSpace,
+    pub offset: RigidTransform3D<f32, ApiSpace, ApiSpace>,
+}