Filter out webidl files based on special comments, and feature-gate webxr interfaces. (#34348)

* Filter out webidl files based on skip-if directives.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* script: Don't build XR functionality without webxr feature.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Fix tidy.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* script: Adjust imports for file movement.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Fix clippy.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Formatting.

Signed-off-by: Josh Matthews <josh@joshmatthews.net>

* Clean up webxr module import.

Co-authored-by: Samson <16504129+sagudev@users.noreply.github.com>
Signed-off-by: Josh Matthews <josh@joshmatthews.net>

---------

Signed-off-by: Josh Matthews <josh@joshmatthews.net>
Co-authored-by: Samson <16504129+sagudev@users.noreply.github.com>

components/script/dom/webxr/xrviewport.rs

@@ -0,0 +1,54 @@
+/* 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/. */
+
+use dom_struct::dom_struct;
+use euclid::Rect;
+use webxr_api::Viewport;
+
+use crate::dom::bindings::codegen::Bindings::XRViewportBinding::XRViewportMethods;
+use crate::dom::bindings::reflector::{reflect_dom_object, Reflector};
+use crate::dom::bindings::root::DomRoot;
+use crate::dom::globalscope::GlobalScope;
+
+#[dom_struct]
+pub struct XRViewport {
+    reflector_: Reflector,
+    #[no_trace]
+    viewport: Rect<i32, Viewport>,
+}
+
+impl XRViewport {
+    fn new_inherited(viewport: Rect<i32, Viewport>) -> XRViewport {
+        XRViewport {
+            reflector_: Reflector::new(),
+            viewport,
+        }
+    }
+
+    pub fn new(global: &GlobalScope, viewport: Rect<i32, Viewport>) -> DomRoot<XRViewport> {
+        reflect_dom_object(Box::new(XRViewport::new_inherited(viewport)), global)
+    }
+}
+
+impl XRViewportMethods<crate::DomTypeHolder> for XRViewport {
+    /// <https://immersive-web.github.io/webxr/#dom-xrviewport-x>
+    fn X(&self) -> i32 {
+        self.viewport.origin.x
+    }
+
+    /// <https://immersive-web.github.io/webxr/#dom-xrviewport-y>
+    fn Y(&self) -> i32 {
+        self.viewport.origin.y
+    }
+
+    /// <https://immersive-web.github.io/webxr/#dom-xrviewport-width>
+    fn Width(&self) -> i32 {
+        self.viewport.size.width
+    }
+
+    /// <https://immersive-web.github.io/webxr/#dom-xrviewport-height>
+    fn Height(&self) -> i32 {
+        self.viewport.size.height
+    }
+}