MediaStream constructor algorithm (section 4.2) in [1] specifies that

"A MediaStream object is said to be MediaStream.inactive when it does not have any tracks or all tracks belonging to the stream have ended. Otherwise the stream is active."

But step 4 in MediaStream constructor algorithm (section 4.2) is checking only whether streams track set is empty for assigning MediaStreams "active" state to true or false. Since according to correction specified in (#25250)[2] there are chances for a MediaStream to contain ended tracks. So it must also check for MediaStreamTracks ended state while assigning "active" state to true or false.

4. If stream's track set is empty, set stream's active attribute to false, otherwise set it to true.

should be corrected as below

4. If stream's track set is empty or all tracks in track set are ended, set stream's active attribute to false, otherwise set it to true.

[1] http://dev.w3.org/2011/webrtc/editor/getusermedia.html#mediastream
[2] https://www.w3.org/Bugs/Public/show_bug.cgi?id=25250