WebXR is going into origin trial in M-66, and the WebVR origin trial is ending in M-68. The two APIs are quite similar, so the current test framework used for WebVR can be used for WebXR with minimal changes. However, we'll need test coverage for both for at least two milestones, so we can't just change everything over to be WebXR-only immediately. The plan of action is:

1. Add any necessary XR functionality to the test framework. This should only be a few Java methods and rewriting the WebVR JavaScript boilerplate code to work for WebXR.

2. Duplicate any relevant tests that use WebVR to have a WebXR version as well. This should be finished by M-66.

3. At some point after M-67 is branched (may wait as long as until M-68 is stable), remove the WebVR tests and any WebVR-only code from the test framework.

4. Refactor/cleanup any remaining references to WebVR