MediaStreamTrack - Web APIs
isolationchange sent whenever the value of the isolated property changes due to the document gaining or losing permission to access the track.
... also available through the onisolationchange event handler property.

RTCPeerConnection - Web APIs
isolationchange sent to the rtcpeerconnection when the isolated property on one of the mediastreamtrack objects associated with the connection changes value.
... also available through the onisolationchange event handler property.