diff --git a/testing/web-platform/tests/resources/chromium/webxr-test.js b/testing/web-platform/tests/resources/chromium/webxr-test.js
index 31bf916caf80..e584ea37cb37 100644
--- a/testing/web-platform/tests/resources/chromium/webxr-test.js
+++ b/testing/web-platform/tests/resources/chromium/webxr-test.js
@@ -12,8 +12,9 @@ class ChromeXRTest {
     return Promise.resolve(this.mockVRService_.addRuntime(init_params));
   }
 
-  simulateDeviceDisconnection(device) {
-    this.mockVRService_.removeRuntime(device);
+  disconnectAllDevices() {
+    this.mockVRService_.removeAllRuntimes(device);
+    return Promise.resolve();
   }
 
   simulateUserActivation(callback) {
@@ -60,11 +61,11 @@ class MockVRService {
     return runtime;
   }
 
-  removeRuntime(runtime) {
-    // We have no way of distinguishing between devices, so just clear the
-    // entire list for now.
-    // TODO(http://crbug.com/873409) We also have no way right now to disconnect
-    // devices.
+  removeAllRuntimes() {
+    if (this.client_) {
+      this.client_.onDeviceChanged();
+    }
+
     this.runtimes_ = [];
   }
 
@@ -151,6 +152,8 @@ class MockRuntime {
 
     this.framesOfReference = {};
 
+    // Initialize DisplayInfo first to set the defaults, then override with
+    // anything from the deviceInit
     if (fakeDeviceInit.supportsImmersive) {
       this.displayInfo_ = this.getImmersiveDisplayInfo();
     } else {
@@ -160,16 +163,16 @@ class MockRuntime {
     if (fakeDeviceInit.supportsEnvironmentIntegration) {
       this.displayInfo_.capabilities.canProvideEnvironmentIntegration = true;
     }
-  }
 
-  // Test methods.
-  setXRPresentationFrameData(poseMatrix, views) {
-    if (poseMatrix == null) {
-      this.pose_ = null;
-    } else {
-      this.setPoseFromMatrix(poseMatrix);
+    if (fakeDeviceInit.viewerOrigin != null) {
+      this.setViewerOrigin(fakeDeviceInit.viewerOrigin);
     }
 
+    this.setViews(fakeDeviceInit.views);
+  }
+
+  // Test API methods.
+  setViews(views) {
     if (views) {
       let changed = false;
       for (let i = 0; i < views.length; i++) {
@@ -182,17 +185,18 @@ class MockRuntime {
         }
       }
 
-      if (changed) {
+      if (changed && this.sessionClient_.ptr.isBound()) {
         this.sessionClient_.onChanged(this.displayInfo_);
       }
     }
   }
 
-
-  setPoseFromMatrix(poseMatrix) {
+  setViewerOrigin(origin, emulatedPosition = false) {
+    let p = origin.position;
+    let q = origin.orientation;
     this.pose_ = {
-      orientation: null,
-      position: null,
+      orientation: { x: q[0], y: q[1], z: q[2], w: q[3] },
+      position: { x: p[0], y: p[1], z: p[2] },
       angularVelocity: null,
       linearVelocity: null,
       angularAcceleration: null,
@@ -200,37 +204,13 @@ class MockRuntime {
       inputState: null,
       poseIndex: 0
     };
-
-    let pose = this.poseFromMatrix(poseMatrix);
-    for (let field in pose) {
-      if (this.pose_.hasOwnProperty(field)) {
-        this.pose_[field] = pose[field];
-      }
-    }
   }
 
-  poseFromMatrix(m) {
-    let m00 = m[0];
-    let m11 = m[5];
-    let m22 = m[10];
-
-    // The max( 0, ... ) is just a safeguard against rounding error.
-    let orientation = new gfx.mojom.Quaternion();
-    orientation.w = Math.sqrt(Math.max(0, 1 + m00 + m11 + m22)) / 2;
-    orientation.x = Math.sqrt(Math.max(0, 1 + m00 - m11 - m22)) / 2;
-    orientation.y = Math.sqrt(Math.max(0, 1 - m00 + m11 - m22)) / 2;
-    orientation.z = Math.sqrt(Math.max(0, 1 - m00 - m11 + m22)) / 2;
-
-    let position = new gfx.mojom.Point3F();
-    position.x = m[12];
-    position.y = m[13];
-    position.z = m[14];
-
-    return {
-      orientation, position
-    }
+  clearViewerOrigin() {
+    this.pose_ = null;
   }
 
+  // Helper methods
   getNonImmersiveDisplayInfo() {
     let displayInfo = this.getImmersiveDisplayInfo();
 
@@ -296,6 +276,8 @@ class MockRuntime {
     let upTan = (1 + m[9]) / m[5];
     let downTan = (1 - m[9]) / m[5];
 
+    let offset = fakeXRViewInit.viewOffset.position;
+
     return {
       fieldOfView: {
         upDegrees: toDegrees(upTan),
@@ -303,9 +285,9 @@ class MockRuntime {
         leftDegrees: toDegrees(leftTan),
         rightDegrees: toDegrees(rightTan)
       },
-      offset: { x: 0, y: 0, z: 0 },
-      renderWidth: 20,
-      renderHeight: 20
+      offset: { x: offset[0], y: offset[1], z: offset[2] },
+      renderWidth: fakeXRViewInit.resolution.width,
+      renderHeight: fakeXRViewInit.resolution.height
     };
   }
 
@@ -405,6 +387,7 @@ class MockRuntime {
   };
 }
 
+// Mojo helper classes
 class MockXRPresentationProvider {
   constructor() {
     this.binding_ = new mojo.Binding(device.mojom.XRPresentationProvider, this);
@@ -448,4 +431,21 @@ class MockXRPresentationProvider {
   }
 }
 
+// This is a temporary workaround for the fact that spinning up webxr before
+// the mojo interceptors are created will cause the interceptors to not get
+// registered, so we have to create this before we query xr;
 let XRTest = new ChromeXRTest();
+
+// This test API is also used to run Chrome's internal legacy VR tests; however,
+// those fail if navigator.xr has been used. Those tests will set a bool telling
+// us not to try to check navigator.xr
+if ((typeof legacy_vr_test === 'undefined') || !legacy_vr_test) {
+  // Some tests may run in the http context where navigator.xr isn't exposed
+  // This should just be to test that it isn't exposed, but don't try to set up
+  // the test framework in this case.
+  if (navigator.xr) {
+    navigator.xr.test = XRTest;
+  }
+} else {
+  navigator.vr = { test: XRTest };
+}
diff --git a/testing/web-platform/tests/webxr/resources/test-constants.js b/testing/web-platform/tests/webxr/resources/test-constants.js
deleted file mode 100644
index aab0417aed0b..000000000000
--- a/testing/web-platform/tests/webxr/resources/test-constants.js
+++ /dev/null
@@ -1,32 +0,0 @@
-// assert_equals can fail when comparing floats due to precision errors, so
-// use assert_approx_equals with this constant instead
-const FLOAT_EPSILON = 0.001;
-
-// Identity matrix
-const IDENTITY_MATRIX = [1, 0, 0, 0,
-                         0, 1, 0, 0,
-                         0, 0, 1, 0,
-                         0, 0, 0, 1];
-
-// A valid pose matrix for  when we don't care about specific values
-const VALID_POSE_MATRIX = [0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1];
-
-const VALID_PROJECTION_MATRIX =
-    [1, 0, 0, 0, 0, 1, 0, 0, 3, 2, -1, -1, 0, 0, -0.2, 0];
-
-const VALID_VIEW_MATRIX = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
-
-// A valid VRPose for when we want the HMD to report being at the origin
-const ORIGIN_POSE = IDENTITY_MATRIX;
-
-// A valid input grip matrix for  when we don't care about specific values
-const VALID_GRIP = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
-
-// A valid input pointer offset for  when we don't care about specific values
-const VALID_POINTER_OFFSET = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 1, 1];
-
-const VALID_GRIP_WITH_POINTER_OFFSET =
-    [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 3, 1];
-
-const VALID_STAGE_TRANSFORM =
-    [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 1.0, 1.65, -1.0, 1];
diff --git a/testing/web-platform/tests/webxr/resources/webxr_test_constants.js b/testing/web-platform/tests/webxr/resources/webxr_test_constants.js
index c38c012ba846..a846f1da75fe 100644
--- a/testing/web-platform/tests/webxr/resources/webxr_test_constants.js
+++ b/testing/web-platform/tests/webxr/resources/webxr_test_constants.js
@@ -8,17 +8,26 @@ const IDENTITY_MATRIX = [1, 0, 0, 0,
                          0, 0, 1, 0,
                          0, 0, 0, 1];
 
-// A valid pose matrix for  when we don't care about specific values
-const VALID_POSE_MATRIX = [0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1];
+const IDENTITY_TRANSFORM = {
+    position: [0, 0, 0],
+    orientation: [0, 0, 0, 1],
+};
+
+// A valid pose matrix/transform for  when we don't care about specific values
+// Note that these two should be identical, just different representations
+const VALID_POSE_MATRIX = [0, 1, 0, 0,
+                           0, 0, 1, 0,
+                           1, 0, 0, 0,
+                           1, 1, 1, 1];
+
+const VALID_POSE_TRANSFORM = {
+    position: [1, 1, 1],
+    orientation: [0.5, 0.5, 0.5, 0.5]
+};
 
 const VALID_PROJECTION_MATRIX =
     [1, 0, 0, 0, 0, 1, 0, 0, 3, 2, -1, -1, 0, 0, -0.2, 0];
 
-const VALID_VIEW_MATRIX = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
-
-// A valid VRPose for when we want the HMD to report being at the origin
-const ORIGIN_POSE = IDENTITY_MATRIX;
-
 // A valid input grip matrix for  when we don't care about specific values
 const VALID_GRIP = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
 
@@ -39,3 +48,51 @@ const VALID_BOUNDS = [
     { x: -3.5, y: 0, z: 0.0 },
     { x: -3.0, y: 0, z: -2.0 }
 ];
+
+const VALID_RESOLUTION = {
+    width: 20,
+    height: 20
+};
+
+const LEFT_OFFSET = {
+    position: [-0.1, 0, 0],
+    orientation: [0, 0, 0, 1]
+};
+
+const RIGHT_OFFSET = {
+    position: [0.1, 0, 0],
+    orientation: [0, 0, 0, 1]
+};
+
+const VALID_VIEWS = [{
+        eye:"left",
+        projectionMatrix: VALID_PROJECTION_MATRIX,
+        viewOffset: LEFT_OFFSET,
+        resolution: VALID_RESOLUTION
+    }, {
+        eye:"right",
+        projectionMatrix: VALID_PROJECTION_MATRIX,
+        viewOffset: RIGHT_OFFSET,
+        resolution: VALID_RESOLUTION
+    },
+];
+
+const NON_IMMERSIVE_VIEWS = [{
+        eye: "none",
+        projectionMatrix: VALID_PROJECTION_MATRIX,
+        viewOffset: IDENTITY_TRANSFORM,
+        resolution: VALID_RESOLUTION,
+    }
+];
+
+const TRACKED_IMMERSIVE_DEVICE = {
+    supportsImmersive: true,
+    views: VALID_VIEWS,
+    viewerOrigin: IDENTITY_TRANSFORM
+};
+
+const VALID_NON_IMMERSIVE_DEVICE = {
+    supportsImmersive: false,
+    views: NON_IMMERSIVE_VIEWS,
+    viewerOrigin: IDENTITY_TRANSFORM
+};
diff --git a/testing/web-platform/tests/webxr/resources/webxr_util.js b/testing/web-platform/tests/webxr/resources/webxr_util.js
index 860d363f2c96..54a91c85c86a 100644
--- a/testing/web-platform/tests/webxr/resources/webxr_util.js
+++ b/testing/web-platform/tests/webxr/resources/webxr_util.js
@@ -39,15 +39,15 @@ function xr_session_promise_test(
 
   xr_promise_test(
       name,
-      (t) =>
-          XRTest.simulateDeviceConnection(fakeDeviceInit)
+      (t) =>{
+          return navigator.xr.test.simulateDeviceConnection(fakeDeviceInit)
               .then((controller) => {
                 testDeviceController = controller;
                 return gl.makeXRCompatible();
               })
               .then(() => new Promise((resolve, reject) => {
                       // Perform the session request in a user gesture.
-                      XRTest.simulateUserActivation(() => {
+                      navigator.xr.test.simulateUserActivation(() => {
                         navigator.xr.requestSession(sessionMode)
                             .then((session) => {
                               testSession = session;
@@ -75,8 +75,9 @@ function xr_session_promise_test(
               .then(() => {
                 // Cleanup system state.
                 testSession.end().catch(() => {});
-                XRTest.simulateDeviceDisconnection();
-              }),
+                return navigator.xr.test.disconnectAllDevices();
+              })
+            },
       properties);
 }
 
@@ -138,4 +139,4 @@ let loadChromiumResources = Promise.resolve().then(() => {
   });
 
   return chain;
-});
\ No newline at end of file
+});
diff --git a/testing/web-platform/tests/webxr/webGLCanvasContext_create_xrcompatible.https.html b/testing/web-platform/tests/webxr/webGLCanvasContext_create_xrcompatible.https.html
index 8b2f196fa76e..b83b9601aed1 100644
--- a/testing/web-platform/tests/webxr/webGLCanvasContext_create_xrcompatible.https.html
+++ b/testing/web-platform/tests/webxr/webGLCanvasContext_create_xrcompatible.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas id="webgl-canvas"></canvas>
   <script>
     xr_promise_test("An XR-compatible webglCanvasContext can be created",
       (t) => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+        return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
           .then( (controller) => {
             webglCanvas = document.getElementById('webgl-canvas');
             gl = webglCanvas.getContext('webgl', {xrCompatible: true});
diff --git a/testing/web-platform/tests/webxr/webGLCanvasContext_makecompatible_contextlost.https.html b/testing/web-platform/tests/webxr/webGLCanvasContext_makecompatible_contextlost.https.html
index 3102008c57db..0e3dbfc97f98 100644
--- a/testing/web-platform/tests/webxr/webGLCanvasContext_makecompatible_contextlost.https.html
+++ b/testing/web-platform/tests/webxr/webGLCanvasContext_makecompatible_contextlost.https.html
@@ -3,13 +3,14 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas id="webgl-canvas"></canvas>
   <script>
 
     xr_promise_test(
       "A lost webglCanvasContext should not be able to set xr compatibility",
      (t) => {
-      return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+      return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
         .then( (controller) => {
           webglCanvas = document.getElementById('webgl-canvas');
           gl = webglCanvas.getContext('webgl', {xrCompatible: true});
diff --git a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive.https.html b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive.https.html
index 50a9d344541c..a397d1a89f6e 100644
--- a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive.https.html
@@ -3,12 +3,13 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
   <script>
     xr_session_promise_test(
       "Tests requestSession resolves when supported",
       (session) => {
         assert_not_equals(session, null);
-      }, { supportsImmersive:true }, 'immersive-vr');
+      }, TRACKED_IMMERSIVE_DEVICE, 'immersive-vr');
   </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_no_gesture.https.html b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_no_gesture.https.html
index eb5a4fda0bdf..10e15b63244d 100644
--- a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_no_gesture.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_no_gesture.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "Requesting immersive session outside of a user gesture rejects",
       (t) => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+        return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
           .then( (controller) => promise_rejects(
             t, 'SecurityError', navigator.xr.requestSession('immersive-vr')));
       });
diff --git a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_unsupported.https.html b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_unsupported.https.html
index 2592f3a4a0d4..6c0e6284a420 100644
--- a/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_unsupported.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_requestSession_immersive_unsupported.https.html
@@ -3,13 +3,14 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "Requesting an immersive session when unsupported rejects",
       (t) => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:false })
+        return navigator.xr.test.simulateDeviceConnection(VALID_NON_IMMERSIVE_DEVICE)
           .then( (controller) => new Promise((resolve) => {
-            XRTest.simulateUserActivation( () => {
+            navigator.xr.test.simulateUserActivation( () => {
               resolve(promise_rejects(
                 t,
                 "NotSupportedError",
diff --git a/testing/web-platform/tests/webxr/xrDevice_requestSession_no_mode.https.html b/testing/web-platform/tests/webxr/xrDevice_requestSession_no_mode.https.html
index c4ac3f6b6d77..de77b38c868e 100644
--- a/testing/web-platform/tests/webxr/xrDevice_requestSession_no_mode.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_requestSession_no_mode.https.html
@@ -3,13 +3,14 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "Requesting a session with no mode rejects",
       (t) => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:false })
+        return navigator.xr.test.simulateDeviceConnection(VALID_NON_IMMERSIVE_DEVICE)
           .then( (controller) => new Promise((resolve) => {
-            XRTest.simulateUserActivation( () => {
+            navigator.xr.test.simulateUserActivation( () => {
               resolve(promise_rejects(
                 t,
                 new TypeError(),
diff --git a/testing/web-platform/tests/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html b/testing/web-platform/tests/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html
index 40e6f4928b3f..599505925585 100644
--- a/testing/web-platform/tests/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_requestSession_non_immersive_no_gesture.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "Requesting non-immersive session outside of a user gesture succeeds",
       (t) => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:false })
+        return navigator.xr.test.simulateDeviceConnection(VALID_NON_IMMERSIVE_DEVICE)
           .then( (controller) => navigator.xr.requestSession('inline'))
           .then( (session) => { assert_not_equals(session, null); });
       });
diff --git a/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive.https.html b/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive.https.html
index 53dd41e3d27d..fd0827a526ef 100644
--- a/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "supportsSession resolves when immersive options supported",
       () => {
-        return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+        return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
           .then( (controller) => navigator.xr.supportsSession('immersive-vr'));
       });
   </script>
diff --git a/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive_unsupported.https.html b/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive_unsupported.https.html
index 0fb44a895d1f..1d63a2b1c3a2 100644
--- a/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive_unsupported.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_supportsSession_immersive_unsupported.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "supportsSession rejects when options not supported",
       (t) => {
-      return XRTest.simulateDeviceConnection({ supportsImmersive:false })
+      return navigator.xr.test.simulateDeviceConnection(VALID_NON_IMMERSIVE_DEVICE)
         .then( (controller) => {
           return promise_rejects(
             t,
diff --git a/testing/web-platform/tests/webxr/xrDevice_supportsSession_non_immersive.https.html b/testing/web-platform/tests/webxr/xrDevice_supportsSession_non_immersive.https.html
index d5191400c449..b376495d7651 100644
--- a/testing/web-platform/tests/webxr/xrDevice_supportsSession_non_immersive.https.html
+++ b/testing/web-platform/tests/webxr/xrDevice_supportsSession_non_immersive.https.html
@@ -3,11 +3,12 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <script>
     xr_promise_test(
       "supportsSession resolves when inline options supported",
       (t) => {
-      return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+      return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
         .then( (controller) => {
           // Inline sessions should be supported.
           return navigator.xr.supportsSession('inline');
diff --git a/testing/web-platform/tests/webxr/xrFrame_getPose.https.html b/testing/web-platform/tests/webxr/xrFrame_getPose.https.html
index 243fb8cd6661..50e8abf145b9 100644
--- a/testing/web-platform/tests/webxr/xrFrame_getPose.https.html
+++ b/testing/web-platform/tests/webxr/xrFrame_getPose.https.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="resources/test-constants.js"></script>
+<script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_util.js"></script>
 <script src="resources/xr-test-asserts.js"></script>
 <canvas></canvas>
@@ -11,20 +11,9 @@
 let immersiveTestName = "XRFrame.getPose works for immersive sessions";
 let nonImmersiveTestName = "XRFrame.getPose works for non-immersive sessions";
 
-let fakeDeviceInitParams = { supportsImmersive:true };
+let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
 let testFunction = function(session, fakeDeviceController, t) {
-  // Need to have a valid pose or input events don't process.
-  fakeDeviceController.setXRPresentationFrameData(VALID_POSE_MATRIX, [{
-      eye:"left",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }, {
-      eye:"right",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }]);
-
   return Promise.all([
     session.requestReferenceSpace('local'),
     session.requestReferenceSpace('local')
diff --git a/testing/web-platform/tests/webxr/xrFrame_lifetime.https.html b/testing/web-platform/tests/webxr/xrFrame_lifetime.https.html
index 27ef02de3374..c7af792c7bb4 100644
--- a/testing/web-platform/tests/webxr/xrFrame_lifetime.https.html
+++ b/testing/web-platform/tests/webxr/xrFrame_lifetime.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
@@ -11,7 +12,7 @@
     let nonImmersiveTestName = "XRFrame methods throw exceptions outside of the " +
       "requestAnimationFrame callback for non-immersive sessions";
 
-    let fakeDeviceInitParams = { supportsImmersive:true };
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = (testSession, testController, t) => new Promise((resolve) => {
       let staleFrame = null;
@@ -54,4 +55,4 @@
       fakeDeviceInitParams, 'inline');
 
   </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/testing/web-platform/tests/webxr/xrRay_constructor.https.html b/testing/web-platform/tests/webxr/xrRay_constructor.https.html
index ebf88845b0cd..b955db4509c2 100644
--- a/testing/web-platform/tests/webxr/xrRay_constructor.https.html
+++ b/testing/web-platform/tests/webxr/xrRay_constructor.https.html
@@ -3,7 +3,6 @@
 <script src="/resources/testharnessreport.js"></script>
 <script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_test_asserts.js"></script>
-
 <script>
 
 let constructor_test_name = "XRRay constructors work";
diff --git a/testing/web-platform/tests/webxr/xrRay_matrix.https.html b/testing/web-platform/tests/webxr/xrRay_matrix.https.html
index 85d7bffb87b7..83a1050d6b16 100644
--- a/testing/web-platform/tests/webxr/xrRay_matrix.https.html
+++ b/testing/web-platform/tests/webxr/xrRay_matrix.https.html
@@ -4,7 +4,6 @@
 <script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_test_asserts.js"></script>
 <script src="resources/webxr_math_utils.js"></script>
-
 <script>
 
 let matrix_tests_name = "XRRay matrix works";
diff --git a/testing/web-platform/tests/webxr/xrRigidTransform_constructor.https.html b/testing/web-platform/tests/webxr/xrRigidTransform_constructor.https.html
index 15666973473a..6a54fff808d9 100644
--- a/testing/web-platform/tests/webxr/xrRigidTransform_constructor.https.html
+++ b/testing/web-platform/tests/webxr/xrRigidTransform_constructor.https.html
@@ -4,11 +4,10 @@
 <script src="resources/webxr_util.js"></script>
 <script src="resources/webxr_test_constants.js"></script>
 <canvas id="webgl-canvas"></canvas>
-
 <script>
 
 let testName = "XRRigidTransform constructor works";
-let fakeDeviceInitParams = { supportsImmersive: true };
+let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
 let testFunction =
   (session, fakeDeviceController, t) => new Promise((resolve, reject) => {
diff --git a/testing/web-platform/tests/webxr/xrRigidTransform_inverse.https.html b/testing/web-platform/tests/webxr/xrRigidTransform_inverse.https.html
index 706f72102ad3..a314f6b55a21 100644
--- a/testing/web-platform/tests/webxr/xrRigidTransform_inverse.https.html
+++ b/testing/web-platform/tests/webxr/xrRigidTransform_inverse.https.html
@@ -4,11 +4,10 @@
 <script src="resources/webxr_util.js"></script>
 <script src="resources/webxr_test_constants.js"></script>
 <canvas id="webgl-canvas"></canvas>
-
 <script>
 
 let testName = "XRRigidTransform inverse works";
-let fakeDeviceInitParams = { supportsImmersive: true };
+let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
 let testFunction =
   (session, fakeDeviceController, t) => new Promise((resolve, reject) => {
diff --git a/testing/web-platform/tests/webxr/xrRigidTransform_matrix.https.html b/testing/web-platform/tests/webxr/xrRigidTransform_matrix.https.html
index 21236c732461..df804193ffe9 100644
--- a/testing/web-platform/tests/webxr/xrRigidTransform_matrix.https.html
+++ b/testing/web-platform/tests/webxr/xrRigidTransform_matrix.https.html
@@ -4,7 +4,6 @@
 <script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_test_asserts.js"></script>
 <script src="resources/webxr_math_utils.js"></script>
-
 <script>
 
 let matrix_tests_name = "XRRigidTransform matrix works";
diff --git a/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame.https.html b/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame.https.html
index d45349ad2446..6a294f21f06d 100644
--- a/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
@@ -11,7 +12,7 @@
     let nonImmersiveTestName = "XRSession requestAnimationFrame callbacks can be "
       + "unregistered with cancelAnimationFrame for non-immersive sessions";
 
-    let fakeDeviceInitParams = { supportsImmersive:true };
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = (session) => new Promise((resolve, reject) => {
 
diff --git a/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame_invalidhandle.https.html b/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame_invalidhandle.https.html
index b93f4e27909e..51a639b956c8 100644
--- a/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame_invalidhandle.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_cancelAnimationFrame_invalidhandle.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
   <script>
     let immersiveTestName = "XRSession cancelAnimationFrame does not have unexpected "
@@ -10,7 +11,7 @@
     let nonImmersiveTestName = "XRSession cancelAnimationFrame does not have unexpected "
       + "behavior when given invalid handles on non-immersive testSession";
 
-    let fakeDeviceInitParams = { supportsImmersive:true };
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = (testSession) => new Promise((resolve) => {
       let counter = 0;
diff --git a/testing/web-platform/tests/webxr/xrSession_end.https.html b/testing/web-platform/tests/webxr/xrSession_end.https.html
index 26b6b47d2bfe..b91a5b977cab 100644
--- a/testing/web-platform/tests/webxr/xrSession_end.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_end.https.html
@@ -3,13 +3,14 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
     const immersivetestName = "end event fires when immersive session ends";
     const nonimmersiveTestName = "end event fires when non-immersive session ends";
     let watcherDone = new Event("watcherdone");
-    const fakeDeviceInitParams = { supportsImmersive:true };
+    const fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = function(session, testDeviceController, t) {
       let eventWatcher = new EventWatcher(t, session, ["end", "watcherdone"]);
@@ -32,4 +33,4 @@
     xr_session_promise_test(nonimmersiveTestName, testFunction,
       fakeDeviceInitParams, 'inline');
   </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/testing/web-platform/tests/webxr/xrSession_prevent_multiple_exclusive.https.html b/testing/web-platform/tests/webxr/xrSession_prevent_multiple_exclusive.https.html
index e61bd392718a..cd1407037849 100644
--- a/testing/web-platform/tests/webxr/xrSession_prevent_multiple_exclusive.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_prevent_multiple_exclusive.https.html
@@ -3,18 +3,19 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
     xr_promise_test(
       "Test prevention of multiple simultaneous immersive sessions",
       (t) => {
-      return XRTest.simulateDeviceConnection({ supportsImmersive:true })
+      return navigator.xr.test.simulateDeviceConnection(TRACKED_IMMERSIVE_DEVICE)
         .then( (controller) => new Promise((resolve) => {
-          XRTest.simulateUserActivation( () => {
+          navigator.xr.test.simulateUserActivation( () => {
             resolve(navigator.xr.requestSession('immersive-vr')
               .then( (session) => new Promise((resolve) => {
-                XRTest.simulateUserActivation( () => {
+                navigator.xr.test.simulateUserActivation( () => {
                   // Requesting a second immersive session when another immersive
                   // session is active should fail. Immersive sessions
                   // should take up the users entire view, and therefore it should
@@ -27,7 +28,7 @@
                       // End the immersive session and try again. Now the immersive
                       // session creation should succeed.
                       return session.end().then( () => new Promise((resolve) => {
-                        XRTest.simulateUserActivation( () => {
+                        navigator.xr.test.simulateUserActivation( () => {
                           resolve(navigator.xr.requestSession('immersive-vr'));
                         });
                       }));
diff --git a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_callback_calls.https.html b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_callback_calls.https.html
index 2ed468bc3a5a..98231c8e9e70 100644
--- a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_callback_calls.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_callback_calls.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
@@ -11,7 +12,7 @@
     let nonImmersiveTestName = "XRSession requestAnimationFrame calls the " +
       "provided callback a non-immersive session";
 
-    let fakeDeviceInitParams = { supportsImmersive:true };
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = (testSession) => new Promise((resolve) => {
       function onFrame(time, xrFrame) {
@@ -29,4 +30,4 @@
       fakeDeviceInitParams, 'inline');
 
   </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_data_valid.https.html b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_data_valid.https.html
index c5108e4eccf9..760ff3dd657f 100644
--- a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_data_valid.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_data_valid.https.html
@@ -3,31 +3,13 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
     const testName = "RequestAnimationFrame resolves with good data";
 
-    const identityMatrix = new Float32Array([
-      1, 0, 0, 0,
-      0, 1, 0, 0,
-      0, 0, 1, 0,
-      0, 0, 0, 1
-    ]);
-
-    const rightFakeXRViewInit = {
-      eye:"right",
-      projectionMatrix: identityMatrix,
-      viewMatrix: identityMatrix
-    };
-
-    const leftFakeXRViewInit = {
-      eye:"left",
-      projectionMatrix: identityMatrix,
-      viewMatrix: identityMatrix
-    };
-
-    const fakeDeviceInitOptions = { supportsImmersive:true };
+    const fakeDeviceInitOptions = TRACKED_IMMERSIVE_DEVICE;
 
     let testSession;
 
@@ -52,8 +34,8 @@
             let viewerPose = xrFrame.getViewerPose(referenceSpace);
 
             assert_not_equals(viewerPose, null);
-            for(let i = 0; i < identityMatrix.length; i++) {
-              assert_equals(viewerPose.transform.matrix[i], identityMatrix[i]);
+            for(let i = 0; i < IDENTITY_MATRIX.length; i++) {
+              assert_equals(viewerPose.transform.matrix[i], IDENTITY_MATRIX[i]);
             }
 
             assert_not_equals(viewerPose.views, null);
@@ -65,11 +47,6 @@
             resolve();
           }
 
-          testDeviceController.setXRPresentationFrameData(
-            identityMatrix,
-            [rightFakeXRViewInit, leftFakeXRViewInit]
-          );
-
           testSession.requestAnimationFrame(onFrame);
         })
       );
diff --git a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html
index 95d9e7810594..f8587796a229 100644
--- a/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_requestAnimationFrame_getViewerPose.https.html
@@ -3,6 +3,8 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
+  <script src="resources/xr-test-asserts.js"></script>
   <canvas></canvas>
 
   <script>
@@ -12,12 +14,22 @@
     let nonImmersiveTestName =
       "XRFrame getViewerPose updates on the next frame for non-immersive sessions";
 
-    let fakeDeviceInitParams = { supportsImmersive: true };
+    let fakeDeviceInitParams = {
+      supportsImmersive: true,
+      views: VALID_VIEWS
+    };
 
-    // Valid matrices for  when we don't care about specific values
-    const validPoseMatrix = [0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1];
-    const validProjectionMatrix = [1, 0, 0, 0, 0, 1, 0, 0, 3, 2, -1, -1, 0, 0, -0.2, 0];
-    const validViewMatrix = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
+    // A valid pose matrix/transform for  when we don't care about specific values
+    // Note that these two should be identical, just different representations
+    const expectedPoseMatrix = [0, 1, 0, 0,
+                                0, 0, 1, 0,
+                                1, 0, 0, 0,
+                                1, 1, 1, 1];
+
+    const poseTransform = {
+        position: [1, 1, 1],
+        orientation: [0.5, 0.5, 0.5, 0.5]
+    };
 
     let testFunction = function(session, fakeDeviceController, t) {
       return session.requestReferenceSpace('local')
@@ -30,16 +42,7 @@
                 // Expecting to not get a pose since none has been supplied
                 assert_equals(vrFrame.getViewerPose(referenceSpace), null);
 
-                fakeDeviceController.setXRPresentationFrameData(
-                  validPoseMatrix, [{
-                    eye:"left",
-                    projectionMatrix: validProjectionMatrix,
-                    viewMatrix: validViewMatrix
-                  }, {
-                    eye:"right",
-                    projectionMatrix: validProjectionMatrix,
-                    viewMatrix: validViewMatrix
-                  }]);
+                fakeDeviceController.setViewerOrigin(poseTransform);
 
                 // Check that pose does not update pose within the same frame.
                 assert_equals(vrFrame.getViewerPose(referenceSpace), null);
@@ -51,10 +54,7 @@
 
                 let poseMatrix = pose.transform.matrix;
                 assert_not_equals(poseMatrix, null);
-
-                for(let i = 0; i < poseMatrix.length; i++) {
-                  assert_equals(poseMatrix[i], validPoseMatrix[i]);
-                }
+                assert_matrix_approx_equals(poseMatrix, expectedPoseMatrix, FLOAT_EPSILON);
               });
 
               // Finished.
diff --git a/testing/web-platform/tests/webxr/xrSession_requestReferenceSpace.https.html b/testing/web-platform/tests/webxr/xrSession_requestReferenceSpace.https.html
index 2fbf9b977ca1..c90d6ce5a545 100644
--- a/testing/web-platform/tests/webxr/xrSession_requestReferenceSpace.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_requestReferenceSpace.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
   <script>
 
@@ -11,7 +12,7 @@
     let nonImmersiveTestName =
       "Non-immersive XRSession requestReferenceSpace returns expected objects";
 
-    let fakeDeviceInitParams = { supportsImmersive: true };
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = function(session, fakeDeviceController, t) {
       return promise_rejects(t, new TypeError(), session.requestReferenceSpace('foo'))
@@ -61,4 +62,4 @@
       nonImmersiveTestName, testFunction, fakeDeviceInitParams, 'inline');
 
   </script>
-</body>
\ No newline at end of file
+</body>
diff --git a/testing/web-platform/tests/webxr/xrSession_viewer_referenceSpace.https.html b/testing/web-platform/tests/webxr/xrSession_viewer_referenceSpace.https.html
index 85e5e87f8266..fd6082bc3468 100644
--- a/testing/web-platform/tests/webxr/xrSession_viewer_referenceSpace.https.html
+++ b/testing/web-platform/tests/webxr/xrSession_viewer_referenceSpace.https.html
@@ -3,6 +3,7 @@
   <script src=/resources/testharness.js></script>
   <script src=/resources/testharnessreport.js></script>
   <script src="resources/webxr_util.js"></script>
+  <script src="resources/webxr_test_constants.js"></script>
   <canvas></canvas>
 
   <script>
@@ -12,14 +13,7 @@
     let inlineTestName =
       "Identity reference space provides correct poses for inline sessions";
 
-    let fakeDeviceInitParams = { supportsImmersive: true };
-
-    const identityMatrix = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1];
-
-    // Valid matrices for  when we don't care about specific values
-    const validPoseMatrix = [0, 1, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 1, 1, 1, 1];
-    const validProjectionMatrix = [1, 0, 0, 0, 0, 1, 0, 0, 3, 2, -1, -1, 0, 0, -0.2, 0];
-    const validViewMatrix = [1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 0, 4, 3, 2, 1];
+    let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
     let testFunction = function(session, fakeDeviceController, t) {
       return session.requestReferenceSpace('viewer')
@@ -37,19 +31,10 @@
                 assert_not_equals(poseMatrix, null);
 
                 for(let i = 0; i < poseMatrix.length; i++) {
-                  assert_equals(poseMatrix[i], identityMatrix[i]);
+                  assert_equals(poseMatrix[i], IDENTITY_MATRIX[i]);
                 }
 
-                fakeDeviceController.setXRPresentationFrameData(
-                  validPoseMatrix, [{
-                    eye:"left",
-                    projectionMatrix: validProjectionMatrix,
-                    viewMatrix: validViewMatrix
-                  }, {
-                    eye:"right",
-                    projectionMatrix: validProjectionMatrix,
-                    viewMatrix: validViewMatrix
-                  }]);
+                fakeDeviceController.setViewerOrigin(VALID_POSE_TRANSFORM);
               });
             } else {
               t.step( () => {
@@ -62,7 +47,7 @@
                 assert_not_equals(poseMatrix, null);
 
                 for(let i = 0; i < poseMatrix.length; i++) {
-                  assert_equals(poseMatrix[i], identityMatrix[i]);
+                  assert_equals(poseMatrix[i], IDENTITY_MATRIX[i]);
                 }
               });
 
diff --git a/testing/web-platform/tests/webxr/xrView_eyes.https.html b/testing/web-platform/tests/webxr/xrView_eyes.https.html
index 8090bcebadb3..4ff22ff618d9 100644
--- a/testing/web-platform/tests/webxr/xrView_eyes.https.html
+++ b/testing/web-platform/tests/webxr/xrView_eyes.https.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="resources/test-constants.js"></script>
+<script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_util.js"></script>
 <script src="resources/xr-test-asserts.js"></script>
 <canvas></canvas>
@@ -11,20 +11,9 @@
 let immersiveTestName = "XRView.eye is correct for immersive sessions";
 let nonImmersiveTestName = "XRView.eye is correct for non-immersive sessions";
 
-let fakeDeviceInitParams = { supportsImmersive:true };
+let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
 let testFunction = function(session, fakeDeviceController, t) {
-  // Need to have a valid pose or input events don't process.
-  fakeDeviceController.setXRPresentationFrameData(VALID_POSE_MATRIX, [{
-      eye:"left",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }, {
-      eye:"right",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }]);
-
   return session.requestReferenceSpace('viewer')
       .then((space) => new Promise((resolve) => {
     function onFrame(time, xrFrame) {
diff --git a/testing/web-platform/tests/webxr/xrWebGLLayer_viewports.https.html b/testing/web-platform/tests/webxr/xrWebGLLayer_viewports.https.html
index f789e4733548..247e3b779d61 100644
--- a/testing/web-platform/tests/webxr/xrWebGLLayer_viewports.https.html
+++ b/testing/web-platform/tests/webxr/xrWebGLLayer_viewports.https.html
@@ -1,7 +1,7 @@
 <!DOCTYPE html>
 <script src="/resources/testharness.js"></script>
 <script src="/resources/testharnessreport.js"></script>
-<script src="resources/test-constants.js"></script>
+<script src="resources/webxr_test_constants.js"></script>
 <script src="resources/webxr_util.js"></script>
 <script src="resources/xr-test-asserts.js"></script>
 <canvas></canvas>
@@ -11,20 +11,9 @@
 let immersiveTestName = "XRWebGLLayer reports a valid viewports for immersive sessions";
 let inlineTestName = "XRWebGLLayer reports a valid viewports for inline sessions";
 
-let fakeDeviceInitParams = { supportsImmersive:true };
+let fakeDeviceInitParams = TRACKED_IMMERSIVE_DEVICE;
 
 let testFunction = function(session, fakeDeviceController, t) {
-  // Need to have a valid pose.
-  fakeDeviceController.setXRPresentationFrameData(VALID_POSE_MATRIX, [{
-      eye:"left",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }, {
-      eye:"right",
-      projectionMatrix: VALID_PROJECTION_MATRIX,
-      viewMatrix: VALID_VIEW_MATRIX
-    }]);
-
   return session.requestReferenceSpace('viewer')
       .then((space) => new Promise((resolve) => {
     function onFrame(time, xrFrame) {