https://w3c.github.io/mediacapture-main/#media-stream-track-interface-definition Note: getConstraints() must return the exact same object as the object passed into the last successful applyConstraints() call: In step 3.4 of the applyConstraints algorithm, "Finally, resolve p. From this point on until applyConstraints() is called successfully again, getConstraints() must return the newConstraints that were passed as an argument to this call."
<rdar://problem/27776560>