Merge webxr repository (#35228)

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

components/shared/webxr/error.rs

@@ -0,0 +1,21 @@
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+#[cfg(feature = "ipc")]
+use serde::{Deserialize, Serialize};
+
+/// Errors that can be produced by XR.
+
+// TODO: this is currently incomplete!
+
+#[derive(Debug)]
+#[cfg_attr(feature = "ipc", derive(Serialize, Deserialize))]
+pub enum Error {
+    NoMatchingDevice,
+    CommunicationError,
+    ThreadCreationError,
+    InlineSession,
+    UnsupportedFeature(String),
+    BackendSpecific(String),
+}