when event handler will be triggered on MediaStreamTrack

Hi,
According to the spec, http://dev.w3.org/2011/webrtc/editor/getusermedia.html#mediastreamtrack

For MediaStreamTrack object, when event handler will be triggered is not introduced in the spec. Such as onmute, onunmute and onended.
And the related examples are missed as well.
Do you think the webkit test is correct?
You can get test from: https://trac.webkit.org/browser/trunk/LayoutTests/fast/mediastream/MediaStreamTrack.html

Any comments will be appreciated.

Thanks,
Li Yin