This is a testharness.js-based test.
[FAIL] setMetadata() allows changes when AllowRTCEncodedVideoFrameSetMetadataAllFields is enabled
  promise_test: Unhandled rejection with value: object "InvalidModificationError: Failed to execute 'setMetadata' on 'RTCEncodedVideoFrame': Cannot setMetadata: invalid modification of RTCEncodedVideoFrameMetadata."
Harness: the test ran to completion.