diff --git a/Cargo.lock b/Cargo.lock
index 971672f5dd5..51a325d4ffa 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -6389,7 +6389,7 @@ dependencies = [
 [[package]]
 name = "webxr"
 version = "0.0.1"
-source = "git+https://github.com/servo/webxr#29f4f1f28695553c45d6c020172048c0035c49ed"
+source = "git+https://github.com/servo/webxr#b79870164f518d90268aaaac1fb83059b83dceda"
 dependencies = [
  "bindgen",
  "euclid",
@@ -6401,6 +6401,7 @@ dependencies = [
  "serde",
  "surfman",
  "surfman-chains",
+ "time",
  "webxr-api",
  "winapi",
  "wio",
@@ -6409,7 +6410,7 @@ dependencies = [
 [[package]]
 name = "webxr-api"
 version = "0.0.1"
-source = "git+https://github.com/servo/webxr#29f4f1f28695553c45d6c020172048c0035c49ed"
+source = "git+https://github.com/servo/webxr#b79870164f518d90268aaaac1fb83059b83dceda"
 dependencies = [
  "euclid",
  "ipc-channel",
diff --git a/components/script/dom/fakexrdevice.rs b/components/script/dom/fakexrdevice.rs
index d76c94751c0..bb73580e98a 100644
--- a/components/script/dom/fakexrdevice.rs
+++ b/components/script/dom/fakexrdevice.rs
@@ -20,7 +20,7 @@ use ipc_channel::ipc::IpcSender;
 use ipc_channel::router::ROUTER;
 use profile_traits::ipc;
 use std::rc::Rc;
-use webxr_api::{MockDeviceMsg, View, Views};
+use webxr_api::{MockDeviceMsg, MockViewInit, MockViewsInit};
 
 #[dom_struct]
 pub struct FakeXRDevice {
@@ -50,58 +50,57 @@ impl FakeXRDevice {
     }
 }
 
-pub fn get_views(views: &[FakeXRViewInit]) -> Fallible<Views> {
-    if views.len() != 2 {
-        return Err(Error::NotSupported);
-    }
-
-    let (left, right) = match (views[0].eye, views[1].eye) {
-        (XREye::Left, XREye::Right) => (&views[0], &views[1]),
-        (XREye::Right, XREye::Left) => (&views[1], &views[0]),
-        _ => return Err(Error::NotSupported),
-    };
-
-    if left.projectionMatrix.len() != 16 ||
-        right.projectionMatrix.len() != 16 ||
-        left.viewOffset.position.len() != 3 ||
-        right.viewOffset.position.len() != 3
-    {
+pub fn view<Eye>(view: &FakeXRViewInit) -> Fallible<MockViewInit<Eye>> {
+    if view.projectionMatrix.len() != 16 || view.viewOffset.position.len() != 3 {
         return Err(Error::Type("Incorrectly sized array".into()));
     }
 
-    let mut proj_l = [0.; 16];
-    let mut proj_r = [0.; 16];
-    let v: Vec<_> = left.projectionMatrix.iter().map(|x| **x).collect();
-    proj_l.copy_from_slice(&v);
-    let proj_l = Transform3D::from_array(proj_l);
-    let v: Vec<_> = right.projectionMatrix.iter().map(|x| **x).collect();
-    proj_r.copy_from_slice(&v);
-    let proj_r = Transform3D::from_array(proj_r);
+    let mut proj = [0.; 16];
+    let v: Vec<_> = view.projectionMatrix.iter().map(|x| **x).collect();
+    proj.copy_from_slice(&v);
+    let projection = Transform3D::from_array(proj);
 
     // spec defines offsets as origins, but mock API expects the inverse transform
-    let offset_l = get_origin(&left.viewOffset)?.inverse();
-    let offset_r = get_origin(&right.viewOffset)?.inverse();
+    let transform = get_origin(&view.viewOffset)?.inverse();
 
-    let size_l = Size2D::new(views[0].resolution.width, views[0].resolution.height);
-    let size_r = Size2D::new(views[1].resolution.width, views[1].resolution.height);
-
-    let origin_l = Point2D::new(0, 0);
-    let origin_r = Point2D::new(size_l.width, 0);
-
-    let viewport_l = Rect::new(origin_l, size_l);
-    let viewport_r = Rect::new(origin_r, size_r);
-
-    let left = View {
-        projection: proj_l,
-        transform: offset_l,
-        viewport: viewport_l,
+    let size = Size2D::new(view.resolution.width, view.resolution.height);
+    let origin = match view.eye {
+        XREye::Right => Point2D::new(size.width, 0),
+        _ => Point2D::new(0, 0),
     };
-    let right = View {
-        projection: proj_r,
-        transform: offset_r,
-        viewport: viewport_r,
+    let viewport = Rect::new(origin, size);
+
+    let fov = if let Some(ref fov) = view.fieldOfView {
+        Some((
+            fov.leftDegrees.to_radians(),
+            fov.rightDegrees.to_radians(),
+            fov.upDegrees.to_radians(),
+            fov.downDegrees.to_radians(),
+        ))
+    } else {
+        None
     };
-    Ok(Views::Stereo(left, right))
+
+    Ok(MockViewInit {
+        projection,
+        transform,
+        viewport,
+        fov,
+    })
+}
+pub fn get_views(views: &[FakeXRViewInit]) -> Fallible<MockViewsInit> {
+    match views.len() {
+        1 => Ok(MockViewsInit::Mono(view(&views[0])?)),
+        2 => {
+            let (left, right) = match (views[0].eye, views[1].eye) {
+                (XREye::Left, XREye::Right) => (&views[0], &views[1]),
+                (XREye::Right, XREye::Left) => (&views[1], &views[0]),
+                _ => return Err(Error::NotSupported),
+            };
+            Ok(MockViewsInit::Stereo(view(left)?, view(right)?))
+        },
+        _ => Err(Error::NotSupported),
+    }
 }
 
 pub fn get_origin<T, U>(
@@ -134,7 +133,7 @@ impl FakeXRDeviceMethods for FakeXRDevice {
         Ok(())
     }
 
-    /// https://github.com/immersive-web/webxr-test-api/blob/master/explainer.md
+    /// https://immersive-web.github.io/webxr-test-api/#dom-fakexrdevice-setviewerorigin
     fn SetViewerOrigin(
         &self,
         origin: &FakeXRRigidTransformInit,
@@ -142,7 +141,25 @@ impl FakeXRDeviceMethods for FakeXRDevice {
     ) -> Fallible<()> {
         let _ = self
             .sender
-            .send(MockDeviceMsg::SetViewerOrigin(get_origin(origin)?));
+            .send(MockDeviceMsg::SetViewerOrigin(Some(get_origin(origin)?)));
+        Ok(())
+    }
+
+    /// https://immersive-web.github.io/webxr-test-api/#dom-fakexrdevice-clearviewerorigin
+    fn ClearViewerOrigin(&self) {
+        let _ = self.sender.send(MockDeviceMsg::SetViewerOrigin(None));
+    }
+
+    /// https://immersive-web.github.io/webxr-test-api/#dom-fakexrdevice-clearfloororigin
+    fn ClearFloorOrigin(&self) {
+        let _ = self.sender.send(MockDeviceMsg::SetFloorOrigin(None));
+    }
+
+    /// https://immersive-web.github.io/webxr-test-api/#dom-fakexrdevice-setfloororigin
+    fn SetFloorOrigin(&self, origin: &FakeXRRigidTransformInit) -> Fallible<()> {
+        let _ = self
+            .sender
+            .send(MockDeviceMsg::SetFloorOrigin(Some(get_origin(origin)?)));
         Ok(())
     }
 
diff --git a/components/script/dom/webidls/FakeXRDevice.webidl b/components/script/dom/webidls/FakeXRDevice.webidl
index bb008bdc73f..4dde2678435 100644
--- a/components/script/dom/webidls/FakeXRDevice.webidl
+++ b/components/script/dom/webidls/FakeXRDevice.webidl
@@ -13,8 +13,11 @@ interface FakeXRDevice {
   // // behaves as if device was disconnected
   // Promise<void> disconnect();
 
-  // Sets the origin of the viewer
   [Throws] void setViewerOrigin(FakeXRRigidTransformInit origin, optional boolean emulatedPosition = false);
+  void clearViewerOrigin();
+
+  [Throws] void setFloorOrigin(FakeXRRigidTransformInit origin);
+  void clearFloorOrigin();
 
   // // Simulates devices focusing and blurring sessions.
   // void simulateVisibilityChange(XRVisibilityState);
@@ -40,6 +43,8 @@ dictionary FakeXRViewInit {
   required FakeXRRigidTransformInit viewOffset;
   // https://immersive-web.github.io/webxr/#dom-xrwebgllayer-getviewport
   required FakeXRDeviceResolution resolution;
+
+  FakeXRFieldOfViewInit fieldOfView;
 };
 
 // https://immersive-web.github.io/webxr/#xrviewport
@@ -56,3 +61,10 @@ dictionary FakeXRRigidTransformInit {
     required sequence<float> position;
     required sequence<float> orientation;
 };
+
+dictionary FakeXRFieldOfViewInit {
+  required float upDegrees;
+  required float downDegrees;
+  required float leftDegrees;
+  required float rightDegrees;
+};
diff --git a/components/script/dom/webidls/XRRenderState.webidl b/components/script/dom/webidls/XRRenderState.webidl
index 29d0232b21d..e361ced6597 100644
--- a/components/script/dom/webidls/XRRenderState.webidl
+++ b/components/script/dom/webidls/XRRenderState.webidl
@@ -14,6 +14,6 @@ dictionary XRRenderStateInit {
 [SecureContext, Exposed=Window, Pref="dom.webxr.enabled"] interface XRRenderState {
   readonly attribute double depthNear;
   readonly attribute double depthFar;
-  readonly attribute double inlineVerticalFieldOfView;
+  readonly attribute double? inlineVerticalFieldOfView;
   readonly attribute XRWebGLLayer? baseLayer;
 };
diff --git a/components/script/dom/xr.rs b/components/script/dom/xr.rs
index 4f5a90e89c4..72cc573d645 100644
--- a/components/script/dom/xr.rs
+++ b/components/script/dom/xr.rs
@@ -162,12 +162,12 @@ impl XRMethods for XR {
     ) -> Rc<Promise> {
         let promise = Promise::new_in_current_compartment(&self.global(), comp);
 
-        if !ScriptThread::is_user_interacting() {
-            promise.reject_error(Error::Security);
-            return promise;
-        }
-
         if mode != XRSessionMode::Inline {
+            if !ScriptThread::is_user_interacting() {
+                promise.reject_error(Error::Security);
+                return promise;
+            }
+
             if self.pending_or_active_session() {
                 promise.reject_error(Error::InvalidState);
                 return promise;
diff --git a/components/script/dom/xrframe.rs b/components/script/dom/xrframe.rs
index 6c67d896f81..9a752abf759 100644
--- a/components/script/dom/xrframe.rs
+++ b/components/script/dom/xrframe.rs
@@ -77,7 +77,11 @@ impl XRFrameMethods for XRFrame {
             return Err(Error::InvalidState);
         }
 
-        let pose = reference.get_viewer_pose(&self.data);
+        let pose = if let Some(pose) = reference.get_viewer_pose(&self.data) {
+            pose
+        } else {
+            return Ok(None);
+        };
         Ok(Some(XRViewerPose::new(&self.global(), &self.session, pose)))
     }
 
diff --git a/components/script/dom/xrreferencespace.rs b/components/script/dom/xrreferencespace.rs
index 35e106d1125..1116407cf46 100644
--- a/components/script/dom/xrreferencespace.rs
+++ b/components/script/dom/xrreferencespace.rs
@@ -10,10 +10,10 @@ use crate::dom::bindings::reflector::{reflect_dom_object, DomObject};
 use crate::dom::bindings::root::{Dom, DomRoot};
 use crate::dom::globalscope::GlobalScope;
 use crate::dom::xrrigidtransform::XRRigidTransform;
-use crate::dom::xrsession::{cast_transform, ApiPose, ApiRigidTransform, ApiViewerPose, XRSession};
+use crate::dom::xrsession::{cast_transform, ApiPose, ApiViewerPose, XRSession};
 use crate::dom::xrspace::XRSpace;
 use dom_struct::dom_struct;
-use euclid::{RigidTransform3D, Vector3D};
+use euclid::RigidTransform3D;
 use webxr_api::Frame;
 
 #[dom_struct]
@@ -80,8 +80,8 @@ impl XRReferenceSpace {
     ///
     /// This is equivalent to `get_pose(self).inverse() * get_pose(viewerSpace)` (in column vector notation),
     /// however we specialize it to be efficient
-    pub fn get_viewer_pose(&self, base_pose: &Frame) -> ApiViewerPose {
-        let pose = self.get_unoffset_viewer_pose(base_pose);
+    pub fn get_viewer_pose(&self, base_pose: &Frame) -> Option<ApiViewerPose> {
+        let pose = self.get_unoffset_viewer_pose(base_pose)?;
         // in column-vector notation,
         // get_viewer_pose(space) = get_pose(space).inverse() * get_pose(viewer_space)
         //                        = (get_unoffset_pose(space) * offset).inverse() * get_pose(viewer_space)
@@ -89,14 +89,13 @@ impl XRReferenceSpace {
         //                        = offset.inverse() * get_unoffset_viewer_pose(space)
         let offset = self.offset.transform();
         let inverse = offset.inverse();
-        inverse.pre_transform(&pose)
+        Some(inverse.pre_transform(&pose))
     }
 
     /// Gets pose of the viewer with respect to this space
     ///
     /// Does not apply originOffset, use get_viewer_pose instead if you need it
-    pub fn get_unoffset_viewer_pose(&self, base_pose: &Frame) -> ApiViewerPose {
-        let viewer_pose: ApiViewerPose = cast_transform(base_pose.transform);
+    pub fn get_unoffset_viewer_pose(&self, base_pose: &Frame) -> Option<ApiViewerPose> {
         // all math is in column-vector notation
         // we use the following equation to verify correctness here:
         // get_viewer_pose(space) = get_pose(space).inverse() * get_pose(viewer_space)
@@ -105,25 +104,27 @@ impl XRReferenceSpace {
                 // get_viewer_pose(eye_level) = get_pose(eye_level).inverse() * get_pose(viewer_space)
                 //                            = I * viewer_pose
                 //                            = viewer_pose
+                let viewer_pose: ApiViewerPose = cast_transform(base_pose.transform?);
 
                 // we get viewer poses in eye-level space by default
-                viewer_pose
+                Some(viewer_pose)
             },
             XRReferenceSpaceType::Local_floor => {
-                // XXXManishearth support getting floor info from stage parameters
-
                 // get_viewer_pose(floor_level) = get_pose(floor_level).inverse() * get_pose(viewer_space)
-                //                            = Translate(-2).inverse() * viewer_pose
-                //                            = Translate(2) * viewer_pose
+                //                            = floor_to_native.inverse() * viewer_pose
+                //                            = native_to_floor * viewer_pose
+                let viewer_pose = base_pose.transform?;
+                let native_to_floor = self
+                    .upcast::<XRSpace>()
+                    .session()
+                    .with_session(|s| s.floor_transform())?;
 
-                // assume approximate user height of 2 meters
-                let floor_to_eye: ApiRigidTransform = Vector3D::new(0., 2., 0.).into();
-                floor_to_eye.pre_transform(&viewer_pose)
+                Some(cast_transform(native_to_floor.pre_transform(&viewer_pose)))
             },
             XRReferenceSpaceType::Viewer => {
                 // This reference space follows the viewer around, so the viewer is
                 // always at an identity transform with respect to it
-                RigidTransform3D::identity()
+                Some(RigidTransform3D::identity())
             },
             _ => unimplemented!(),
         }
@@ -134,34 +135,34 @@ impl XRReferenceSpace {
     /// The reference origin used is common between all
     /// get_pose calls for spaces from the same device, so this can be used to compare
     /// with other spaces
-    pub fn get_pose(&self, base_pose: &Frame) -> ApiPose {
-        let pose = self.get_unoffset_pose(base_pose);
+    pub fn get_pose(&self, base_pose: &Frame) -> Option<ApiPose> {
+        let pose = self.get_unoffset_pose(base_pose)?;
         let offset = self.offset.transform();
         // pose is a transform from the unoffset space to native space,
         // offset is a transform from offset space to unoffset space,
         // we want a transform from unoffset space to native space,
         // which is pose * offset in column vector notation
-        pose.pre_transform(&offset)
+        Some(pose.pre_transform(&offset))
     }
 
     /// Gets pose represented by this space
     ///
     /// Does not apply originOffset, use get_viewer_pose instead if you need it
-    pub fn get_unoffset_pose(&self, base_pose: &Frame) -> ApiPose {
+    pub fn get_unoffset_pose(&self, base_pose: &Frame) -> Option<ApiPose> {
         match self.ty {
             XRReferenceSpaceType::Local => {
                 // The eye-level pose is basically whatever the headset pose was at t=0, which
                 // for most devices is (0, 0, 0)
-                RigidTransform3D::identity()
+                Some(RigidTransform3D::identity())
             },
             XRReferenceSpaceType::Local_floor => {
-                // XXXManishearth support getting floor info from stage parameters
-
-                // Assume approximate height of 2m
-                // the floor-level space is 2m below the eye-level space, which is (0, 0, 0)
-                Vector3D::new(0., -2., 0.).into()
+                let native_to_floor = self
+                    .upcast::<XRSpace>()
+                    .session()
+                    .with_session(|s| s.floor_transform())?;
+                Some(cast_transform(native_to_floor.inverse()))
             },
-            XRReferenceSpaceType::Viewer => cast_transform(base_pose.transform),
+            XRReferenceSpaceType::Viewer => base_pose.transform.map(cast_transform),
             _ => unimplemented!(),
         }
     }
diff --git a/components/script/dom/xrrenderstate.rs b/components/script/dom/xrrenderstate.rs
index bbaf41385ab..bebcfd7de61 100644
--- a/components/script/dom/xrrenderstate.rs
+++ b/components/script/dom/xrrenderstate.rs
@@ -17,7 +17,7 @@ pub struct XRRenderState {
     reflector_: Reflector,
     depth_near: Cell<f64>,
     depth_far: Cell<f64>,
-    inline_vertical_fov: Cell<f64>,
+    inline_vertical_fov: Cell<Option<f64>>,
     layer: MutNullableDom<XRWebGLLayer>,
 }
 
@@ -25,7 +25,7 @@ impl XRRenderState {
     pub fn new_inherited(
         depth_near: f64,
         depth_far: f64,
-        inline_vertical_fov: f64,
+        inline_vertical_fov: Option<f64>,
         layer: Option<&XRWebGLLayer>,
     ) -> XRRenderState {
         XRRenderState {
@@ -41,7 +41,7 @@ impl XRRenderState {
         global: &GlobalScope,
         depth_near: f64,
         depth_far: f64,
-        inline_vertical_fov: f64,
+        inline_vertical_fov: Option<f64>,
         layer: Option<&XRWebGLLayer>,
     ) -> DomRoot<XRRenderState> {
         reflect_dom_object(
@@ -73,7 +73,8 @@ impl XRRenderState {
         self.depth_far.set(depth)
     }
     pub fn set_inline_vertical_fov(&self, fov: f64) {
-        self.inline_vertical_fov.set(fov)
+        debug_assert!(self.inline_vertical_fov.get().is_some());
+        self.inline_vertical_fov.set(Some(fov))
     }
     pub fn set_layer(&self, layer: Option<&XRWebGLLayer>) {
         self.layer.set(layer)
@@ -92,8 +93,8 @@ impl XRRenderStateMethods for XRRenderState {
     }
 
     /// https://immersive-web.github.io/webxr/#dom-xrrenderstate-inlineverticalfieldofview
-    fn InlineVerticalFieldOfView(&self) -> Finite<f64> {
-        Finite::wrap(self.inline_vertical_fov.get())
+    fn GetInlineVerticalFieldOfView(&self) -> Option<Finite<f64>> {
+        self.inline_vertical_fov.get().map(Finite::wrap)
     }
 
     /// https://immersive-web.github.io/webxr/#dom-xrrenderstate-baselayer
diff --git a/components/script/dom/xrsession.rs b/components/script/dom/xrsession.rs
index bab52ab326f..6e076b6daba 100644
--- a/components/script/dom/xrsession.rs
+++ b/components/script/dom/xrsession.rs
@@ -43,8 +43,10 @@ use dom_struct::dom_struct;
 use euclid::{Rect, RigidTransform3D, Transform3D};
 use ipc_channel::ipc::IpcSender;
 use ipc_channel::router::ROUTER;
+use metrics::ToMs;
 use profile_traits::ipc;
 use std::cell::Cell;
+use std::f64::consts::{FRAC_PI_2, PI};
 use std::mem;
 use std::rc::Rc;
 use webxr_api::{
@@ -72,7 +74,7 @@ pub struct XRSession {
     #[ignore_malloc_size_of = "closures are hard"]
     raf_callback_list: DomRefCell<Vec<(i32, Option<Rc<XRFrameRequestCallback>>)>>,
     #[ignore_malloc_size_of = "defined in ipc-channel"]
-    raf_sender: DomRefCell<Option<IpcSender<(f64, Frame)>>>,
+    raf_sender: DomRefCell<Option<IpcSender<Frame>>>,
     input_sources: Dom<XRInputSourceArray>,
     // Any promises from calling end()
     #[ignore_malloc_size_of = "promises are hard"]
@@ -115,8 +117,12 @@ impl XRSession {
     }
 
     pub fn new(global: &GlobalScope, session: Session, mode: XRSessionMode) -> DomRoot<XRSession> {
-        use std::f64::consts::FRAC_PI_2;
-        let render_state = XRRenderState::new(global, 0.1, 1000.0, FRAC_PI_2, None);
+        let ivfov = if mode == XRSessionMode::Inline {
+            Some(FRAC_PI_2)
+        } else {
+            None
+        };
+        let render_state = XRRenderState::new(global, 0.1, 1000.0, ivfov, None);
         let input_sources = XRInputSourceArray::new(global);
         let ret = reflect_dom_object(
             Box::new(XRSession::new_inherited(
@@ -300,7 +306,7 @@ impl XRSession {
     }
 
     /// https://immersive-web.github.io/webxr/#xr-animation-frame
-    fn raf_callback(&self, (time, mut frame): (f64, Frame)) {
+    fn raf_callback(&self, mut frame: Frame) {
         debug!("WebXR RAF callback");
 
         // Step 1
@@ -333,6 +339,8 @@ impl XRSession {
 
         // Step 4-5
         let mut callbacks = mem::replace(&mut *self.raf_callback_list.borrow_mut(), vec![]);
+        let start = self.global().as_window().get_navigation_start();
+        let time = (frame.time_ns - start).to_ms();
 
         let frame = XRFrame::new(&self.global(), self, frame);
         // Step 6,7
@@ -376,7 +384,10 @@ impl XRSession {
         let near = *render_state.DepthNear() as f32;
         let far = *render_state.DepthFar() as f32;
         clip_planes.update(near, far);
-        let top = *render_state.InlineVerticalFieldOfView() / 2.;
+        let top = *render_state
+            .GetInlineVerticalFieldOfView()
+            .expect("IVFOV should be non null for inline sessions") /
+            2.;
         let top = near * top.tan() as f32;
         let bottom = top;
         let left = top * size.width as f32 / size.height as f32;
@@ -451,7 +462,7 @@ impl XRSessionMethods for XRSession {
         }
 
         // Step 4:
-        if init.inlineVerticalFieldOfView.is_some() {
+        if init.inlineVerticalFieldOfView.is_some() && self.is_immersive() {
             return Err(Error::InvalidState);
         }
 
@@ -459,13 +470,33 @@ impl XRSessionMethods for XRSession {
             .pending_render_state
             .or_init(|| self.active_render_state.get().clone_object());
         if let Some(near) = init.depthNear {
-            pending.set_depth_near(*near);
+            let mut near = *near;
+            // Step 8 from #apply-the-pending-render-state
+            // this may need to be changed if backends wish to impose
+            // further constraints
+            if near < 0. {
+                near = 0.;
+            }
+            pending.set_depth_near(near);
         }
         if let Some(far) = init.depthFar {
+            // Step 9 from #apply-the-pending-render-state
+            // this may need to be changed if backends wish to impose
+            // further constraints
+            // currently the maximum is infinity, so we do nothing
             pending.set_depth_far(*far);
         }
         if let Some(fov) = init.inlineVerticalFieldOfView {
-            pending.set_inline_vertical_fov(*fov);
+            let mut fov = *fov;
+            // Step 10 from #apply-the-pending-render-state
+            // this may need to be changed if backends wish to impose
+            // further constraints
+            if fov < 0. {
+                fov = 0.0001;
+            } else if fov > PI {
+                fov = PI - 0.0001;
+            }
+            pending.set_inline_vertical_fov(fov);
         }
         if let Some(ref layer) = init.baseLayer {
             pending.set_layer(Some(&layer))
diff --git a/components/script/dom/xrspace.rs b/components/script/dom/xrspace.rs
index 29d81fa6afe..652a4345ce2 100644
--- a/components/script/dom/xrspace.rs
+++ b/components/script/dom/xrspace.rs
@@ -68,7 +68,7 @@ impl XRSpace {
     /// with other spaces
     pub fn get_pose(&self, base_pose: &Frame) -> Option<ApiPose> {
         if let Some(reference) = self.downcast::<XRReferenceSpace>() {
-            Some(reference.get_pose(base_pose))
+            reference.get_pose(base_pose)
         } else if let Some(source) = self.input_source.get() {
             // XXXManishearth we should be able to request frame information
             // for inputs when necessary instead of always loading it
diff --git a/components/script/dom/xrtest.rs b/components/script/dom/xrtest.rs
index b40807b25d5..b00a69b8fca 100644
--- a/components/script/dom/xrtest.rs
+++ b/components/script/dom/xrtest.rs
@@ -21,7 +21,6 @@ use crate::dom::promise::Promise;
 use crate::script_thread::ScriptThread;
 use crate::task_source::TaskSource;
 use dom_struct::dom_struct;
-use euclid::RigidTransform3D;
 use ipc_channel::ipc::IpcSender;
 use ipc_channel::router::ROUTER;
 use profile_traits::ipc;
@@ -75,26 +74,26 @@ impl XRTestMethods for XRTest {
 
         let origin = if let Some(ref o) = init.viewerOrigin {
             match get_origin(&o) {
-                Ok(origin) => origin,
+                Ok(origin) => Some(origin),
                 Err(e) => {
                     p.reject_error(e);
                     return p;
                 },
             }
         } else {
-            RigidTransform3D::identity()
+            None
         };
 
         let floor_origin = if let Some(ref o) = init.floorOrigin {
             match get_origin(&o) {
-                Ok(origin) => origin,
+                Ok(origin) => Some(origin),
                 Err(e) => {
                     p.reject_error(e);
                     return p;
                 },
             }
         } else {
-            RigidTransform3D::identity()
+            None
         };
 
         let views = match get_views(&init.views) {
diff --git a/components/script/dom/xrwebgllayer.rs b/components/script/dom/xrwebgllayer.rs
index 752e2ea384a..498a5035ce0 100644
--- a/components/script/dom/xrwebgllayer.rs
+++ b/components/script/dom/xrwebgllayer.rs
@@ -20,7 +20,7 @@ use crate::dom::xrview::XRView;
 use crate::dom::xrviewport::XRViewport;
 use canvas_traits::webgl::WebGLFramebufferId;
 use dom_struct::dom_struct;
-use euclid::Size2D;
+use euclid::{Point2D, Rect, Size2D};
 use std::convert::TryInto;
 use webxr_api::SwapChainId as WebXRSwapChainId;
 use webxr_api::{Viewport, Views};
@@ -211,11 +211,13 @@ impl XRWebGLLayerMethods for XRWebGLLayer {
         let views = self.session.with_session(|s| s.views().clone());
 
         let viewport = match (view.Eye(), views) {
+            (XREye::None, Views::Inline) => {
+                let origin = Point2D::new(0, 0);
+                Rect::new(origin, self.size().cast())
+            },
             (XREye::None, Views::Mono(view)) => view.viewport,
             (XREye::Left, Views::Stereo(view, _)) => view.viewport,
             (XREye::Right, Views::Stereo(_, view)) => view.viewport,
-            // The spec doesn't really say what to do in this case
-            // https://github.com/immersive-web/webxr/issues/769
             _ => return None,
         };
 
diff --git a/tests/wpt/metadata/MANIFEST.json b/tests/wpt/metadata/MANIFEST.json
index 539862864b3..0c2f0111510 100644
--- a/tests/wpt/metadata/MANIFEST.json
+++ b/tests/wpt/metadata/MANIFEST.json
@@ -727760,7 +727760,7 @@
    "testharness"
   ],
   "webxr/xrDevice_requestSession_no_mode.https.html": [
-   "de77b38c868e3b5dad88b8eface770b16b5f16c1",
+   "5ef249c58186131f8e467da48cfafebe65df9adf",
    "testharness"
   ],
   "webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html": [
@@ -727872,7 +727872,7 @@
    "testharness"
   ],
   "webxr/xrSession_requestAnimationFrame_timestamp.https.html": [
-   "2796be9987b5f23e92d5f114fdaa972a5323a37c",
+   "8f5c21cba4015da10b9031f1cf100138e958c46e",
    "testharness"
   ],
   "webxr/xrSession_requestReferenceSpace.https.html": [
@@ -727928,7 +727928,7 @@
    "testharness"
   ],
   "webxr/xrWebGLLayer_constructor.https.html": [
-   "0584da79c12def757f951ec53c4c048f18c39b8c",
+   "dda7ec80310f7ff8aac582a98410886ab4d1b81d",
    "testharness"
   ],
   "webxr/xrWebGLLayer_framebuffer_draw.https.html": [
diff --git a/tests/wpt/metadata/webxr/render_state_vertical_fov_immersive.https.html.ini b/tests/wpt/metadata/webxr/render_state_vertical_fov_immersive.https.html.ini
deleted file mode 100644
index 2ae6711642c..00000000000
--- a/tests/wpt/metadata/webxr/render_state_vertical_fov_immersive.https.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[render_state_vertical_fov_immersive.https.html]
-  [inlineVerticalFieldOfView is set appropriately on immersively sessions]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webxr/render_state_vertical_fov_inline.https.html.ini b/tests/wpt/metadata/webxr/render_state_vertical_fov_inline.https.html.ini
deleted file mode 100644
index d9762ab91bc..00000000000
--- a/tests/wpt/metadata/webxr/render_state_vertical_fov_inline.https.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[render_state_vertical_fov_inline.https.html]
-  [inlineVerticalFieldOfView is set appropriately on inline sessions]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webxr/xrDevice_requestSession_no_mode.https.html.ini b/tests/wpt/metadata/webxr/xrDevice_requestSession_no_mode.https.html.ini
deleted file mode 100644
index a57eb02e024..00000000000
--- a/tests/wpt/metadata/webxr/xrDevice_requestSession_no_mode.https.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[xrDevice_requestSession_no_mode.https.html]
-  [Requesting a session with no mode rejects]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html.ini b/tests/wpt/metadata/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html.ini
deleted file mode 100644
index b6ba334933d..00000000000
--- a/tests/wpt/metadata/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[xrDevice_requestSession_non_immersive_no_gesture.https.html]
-  [Requesting non-immersive session outside of a user gesture succeeds]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html.ini b/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html.ini
deleted file mode 100644
index 5ee23ba9713..00000000000
--- a/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html.ini
+++ /dev/null
@@ -1,7 +0,0 @@
-[xrSession_requestAnimationFrame_getViewerPose.https.html]
-  [XRFrame getViewerPose updates on the next frame for non-immersive sessions]
-    expected: FAIL
-
-  [XRFrame getViewerPose updates on the next frame for immersive sessions]
-    expected: FAIL
-
diff --git a/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_timestamp.https.html.ini b/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_timestamp.https.html.ini
deleted file mode 100644
index 426ad2894ad..00000000000
--- a/tests/wpt/metadata/webxr/xrSession_requestAnimationFrame_timestamp.https.html.ini
+++ /dev/null
@@ -1,8 +0,0 @@
-[xrSession_requestAnimationFrame_timestamp.https.html]
-  expected: TIMEOUT
-  [XRFrame getViewerPose updates on the next frame for immersive]
-    expected: FAIL
-
-  [XRFrame getViewerPose updates on the next frame for non-immersive]
-    expected: TIMEOUT
-
diff --git a/tests/wpt/metadata/webxr/xrWebGLLayer_constructor.https.html.ini b/tests/wpt/metadata/webxr/xrWebGLLayer_constructor.https.html.ini
index f9f55152f51..08a51f5b1bc 100644
--- a/tests/wpt/metadata/webxr/xrWebGLLayer_constructor.https.html.ini
+++ b/tests/wpt/metadata/webxr/xrWebGLLayer_constructor.https.html.ini
@@ -1,4 +1,5 @@
 [xrWebGLLayer_constructor.https.html]
+  expected: ERROR
   [Ensure that XRWebGLLayer's constructor throws appropriate errors]
-    expected: FAIL
+    expected: TIMEOUT
 
diff --git a/tests/wpt/metadata/webxr/xrWebGLLayer_viewports.https.html.ini b/tests/wpt/metadata/webxr/xrWebGLLayer_viewports.https.html.ini
deleted file mode 100644
index c078a042488..00000000000
--- a/tests/wpt/metadata/webxr/xrWebGLLayer_viewports.https.html.ini
+++ /dev/null
@@ -1,4 +0,0 @@
-[xrWebGLLayer_viewports.https.html]
-  [XRWebGLLayer reports a valid viewports for inline sessions]
-    expected: FAIL
-
diff --git a/tests/wpt/web-platform-tests/webxr/xrDevice_requestSession_no_mode.https.html b/tests/wpt/web-platform-tests/webxr/xrDevice_requestSession_no_mode.https.html
index de77b38c868..5ef249c5818 100644
--- a/tests/wpt/web-platform-tests/webxr/xrDevice_requestSession_no_mode.https.html
+++ b/tests/wpt/web-platform-tests/webxr/xrDevice_requestSession_no_mode.https.html
@@ -11,11 +11,10 @@
         return navigator.xr.test.simulateDeviceConnection(VALID_NON_IMMERSIVE_DEVICE)
           .then( (controller) => new Promise((resolve) => {
             navigator.xr.test.simulateUserActivation( () => {
-              resolve(promise_rejects(
-                t,
-                new TypeError(),
-                navigator.xr.requestSession()
-              ))
+              t.step_func(() => {
+                assert_throws(new TypeError(), () => navigator.xr.requestSession())
+              })
+              resolve()
             });
           }));
       });
diff --git a/tests/wpt/web-platform-tests/webxr/xrSession_requestAnimationFrame_timestamp.https.html b/tests/wpt/web-platform-tests/webxr/xrSession_requestAnimationFrame_timestamp.https.html
index 2796be9987b..8f5c21cba40 100644
--- a/tests/wpt/web-platform-tests/webxr/xrSession_requestAnimationFrame_timestamp.https.html
+++ b/tests/wpt/web-platform-tests/webxr/xrSession_requestAnimationFrame_timestamp.https.html
@@ -20,25 +20,23 @@ let testFunction = function(session, fakeDeviceController, t) {
       let counter = 0;
       let windowFrameTime = 0;
       let frameTime = 0;
+      let lastFrameTime = 0;
+      let firstFrame = true;
 
       function onFrameFirst(time, xrFrame) {
+        lastFrameTime = frameTime;
         frameTime = time;
+        firstFrame = false;
         let now = performance.now();
 
         t.step( () => {
           // This callback must be the first one called.
           assert_equals(counter, 0);
 
-          // window.requestAnimationFrame and session.requestAnimationFrame
-          // should be providing timestamps that are on the same scale and
-          // within a resonable margin of error of eachother. This means that
-          // this frame's timestamp should be larger than one provided to a
-          // previous window.requestAnimationFrame and should also be within
-          // a sane delta of it. One minute is probably overly generous here,
-          // but it will at least catch cases where the times are reported with
-          // entirely different bases.
-          assert_greater_than(frameTime, windowFrameTime);
-          assert_approx_equals(frameTime, windowFrameTime, ONE_MINUTE);
+          if (!firstFrame) {
+            assert_greater_than(frameTime, lastFrameTime);
+            assert_approx_equals(frameTime, lastFrameTime, TEN_SECONDS);
+          }
 
           // There's going to be some disparity between performance.now() and
           // the timestamp passed into the callback, but it shouldn't be huge.
@@ -47,6 +45,12 @@ let testFunction = function(session, fakeDeviceController, t) {
           assert_approx_equals(frameTime, now, TEN_SECONDS);
         });
 
+        if (firstFrame) {
+          session.requestAnimationFrame(onFrameFirst);
+        } else {
+          resolve();
+        }
+
         counter++;
       }
 
@@ -65,21 +69,14 @@ let testFunction = function(session, fakeDeviceController, t) {
           // Make sure all the previous callbacks fired as expected.
           assert_equals(counter, 11);
         });
-
-        // Finished.
-        resolve();
       }
 
-      window.requestAnimationFrame((time) => {
-        windowFrameTime = time;
-
-        // Queue up several callbacks
-        session.requestAnimationFrame(onFrameFirst);
-        for (let i = 0; i < 10; ++i) {
-          session.requestAnimationFrame(onFrameSubsequent);
-        }
-        session.requestAnimationFrame(onFrameLast);
-      });
+      session.requestAnimationFrame(onFrameFirst);
+      // Queue up several callbacks
+      for (let i = 0; i < 10; ++i) {
+        session.requestAnimationFrame(onFrameSubsequent);
+      }
+      session.requestAnimationFrame(onFrameLast);
 
     }));
 };
diff --git a/tests/wpt/web-platform-tests/webxr/xrWebGLLayer_constructor.https.html b/tests/wpt/web-platform-tests/webxr/xrWebGLLayer_constructor.https.html
index 0584da79c12..dda7ec80310 100644
--- a/tests/wpt/web-platform-tests/webxr/xrWebGLLayer_constructor.https.html
+++ b/tests/wpt/web-platform-tests/webxr/xrWebGLLayer_constructor.https.html
@@ -31,12 +31,14 @@ xr_promise_test("Ensure that XRWebGLLayer's constructor throws appropriate error
         navigator.xr.test.simulateUserActivation(() => {
           navigator.xr.requestSession('immersive-vr')
           .then((session) => {
-            try {
-              let webglLayerIncompatible = new XRWebGLLayer(session, gl);
-              assert_unreached("XRWebGLLayer should fail when created with a context that is not XRCompatible")
-            } catch (err) {
-              assert_equals(err.name, "InvalidStateError");
-            }
+            t.step_func(() => {
+              try {
+                let webglLayerIncompatible = new XRWebGLLayer(session, gl);
+                assert_unreached("XRWebGLLayer should fail when created with a context that is not XRCompatible")
+              } catch (err) {
+                assert_equals(err.name, "InvalidStateError");
+              }
+            })
 
             gl.makeXRCompatible();