<AWT Dev> [7u-dev] Review request for 8015500: Prevent sending multiple WINDOW_CLOSED events for already disposed windows

[Anton Litvinov]

Hello Anthony and Sergey,

Could you please review this backport of the fix , which was reviewed 
and approved by you for JDK 8, from JDK 8 to JDK 7. The backport fix is 
identical to the original fix. The original fix was reviewed at this 
e-mail alias under the subject "[PATCH] 7168064: 
SwingUtilities.sharedOwnerFrame multiplies window close event" in 2013.

Bug: https://bugs.openjdk.java.net/browse/JDK-8015500
Webrev: http://cr.openjdk.java.net/~alitvinov/8015500/jdk7/webrev.00
JDK 8 webrev: 
http://cr.openjdk.java.net/~anthony/8-59-windowClosedEvents-8015500.1

Thank you,
Anton