Add tests to validate XR compatible request scenarios that should throw

This change adds tests that validate scenarios where requesting XR
compatibility should fail:
- If the WebXR feature policy isn't allowed, a SecurityError is thrown
- If there are no devices available, an InvalidStateError is thrown

A runtime enabled feature is added for WebXR multi GPU that syncs with
the corresponding Chromium feature flag.

Bug: 1124024
Change-Id: Ia79b06ecffa936471a6fd80172717c7724245bf2

resources/chromium/webxr-test.js

@@ -217,8 +217,13 @@ class MockVRService {
   // Only handles asynchronous calls to makeXrCompatible. Synchronous calls are
   // not supported in Javascript.
   makeXrCompatible() {
+    if (this.runtimes_.length == 0) {
+      return Promise.resolve({
+        xrCompatibleResult: device.mojom.XrCompatibleResult.kNoDeviceAvailable
+      });
+    }
     return Promise.resolve({
-      xr_compatible_result: device.mojom.XrCompatibleResult.kAlreadyCompatible
+      xrCompatibleResult: device.mojom.XrCompatibleResult.kAlreadyCompatible
     });
   }
 }

webxr/webGLCanvasContext_create_xrcompatible.https.html

@@ -6,6 +6,15 @@
   <script src="resources/webxr_test_constants.js"></script>
   <canvas id="webgl-canvas"></canvas>
   <script>
+    xr_promise_test("Creating a webglCanvasContext with no device",
+      (t) => {
+        let webglCanvas = document.createElement('canvas');
+        let gl = webglCanvas.getContext('webgl');
+
+        assert_false(gl.getContextAttributes().xrCompatible);
+        return promise_rejects_dom(t, "InvalidStateError", gl.makeXRCompatible());
+      });
+
     xr_promise_test("An XR-compatible webglCanvasContext can be created",
       (t) => {
         let gl = null;
@@ -26,6 +35,5 @@
             assert_true(offscreenGl.getContextAttributes().xrCompatible);
           });
       });
-
   </script>
 </body>

webxr/webxr_feature_policy.https.html

@@ -78,4 +78,20 @@
   });
 
 });
+
+xr_promise_test(
+"Validate xr compatibility requests without xr-spatial-tracking policy",
+(t) => {
+  let canvas = document.createElement('canvas');
+  let gl = canvas.getContext('webgl', {xrCompatible: true});
+
+  t.step(() => {
+    assert_false(gl.getContextAttributes().xrCompatible,
+      "xrCompatibility shouldn't be set when requested without feature policy");
+  });
+
+  return promise_rejects_dom(t, "SecurityError",
+    gl.makeXRCompatible(),
+    "makeXRCompatible should reject without feature policy");
+});
 </script>