Auto merge of #22528 - Manishearth:webxr, r=jdm,MortimerGoro

Preliminary WebXR support

This implements just enough WebXR to display to 3DOF devices in
immersive mode only.

Couple missing things:

 - [ ] Handling reference spaces (even if just supporting eye-level spaces)
 - [x] Spec links
 - [ ] We enter immersive mode when baseLayer is set, but it seems like
we're supposed to do this when requestSession is called (https://github.com/immersive-web/webxr/issues/453)
 - [ ] VR/XR should block less (https://github.com/servo/servo/issues/22505)
 - [x] More pref-gating
 - [x] `views` is a method instead of an attribute because we don't support FrozenArray

<s>Once I add spec links and pref gating</s> this can be landed as-is for further experimentation.

r? @jdm @MortimerGoro

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1 files changed, 18 insertions, 0 deletions

diff --git a/components/script/dom/webidls/XRView.webidl b/components/script/dom/webidls/XRView.webidl
new file mode 100644
index 00000000000..ab81136c28d
--- /dev/null
+++ b/components/script/dom/webidls/XRView.webidl
@@ -0,0 +1,18 @@
+/* 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/. */
+
+// https://immersive-web.github.io/webxr/#xrview-interface
+
+enum XREye {
+  "left",
+  "right"
+};
+
+[SecureContext, Exposed=Window, Pref="dom.webxr.enabled"]
+interface XRView {
+  readonly attribute XREye eye;
+  readonly attribute Float32Array projectionMatrix;
+  readonly attribute Float32Array viewMatrix;
+  // readonly attribute XRRigidTransform transform;
+};