It seems that, starting very recently, there is an issue with the HTML Youtube player that does not fire the pause event on Chrome. So after calling player.pauseVideo();, it is waiting indefinitely for the pause event in order to call onFirstPause (addYouTubeEvent( "pause", onFirstPause );).
This is not happening on Firefox, where the pause event is fired and dispatched correctly.
For now, I hacked by changing addYouTubeEvent( "pause", onFirstPause ); into a timeout after the call to player.pauseVideo(); to call onFirstPause.
Will make a pull request if that works for a while... and if Google does not fix the issue soon.