[9] Review request for 8131066: JavaFX MediaPlayer crashes on dispose with certain MP4s

[David DeHaven]

> Hi David,
> 
> Please review the fix:
> https://bugs.openjdk.java.net/browse/JDK-8131066
> http://cr.openjdk.java.net/~almatvee/8131066/webrev.00/
> 
> Crash happens, because AVPlayer was trying to notify AVFMediaPlayer about frame change after AVFMediaPlayer was released. Fixed by unregistering notification callback before AVFMediaPlayer is released.

Change looks good, approved. I also updated the JBS issue.

-DrD-