[7u6] Please review my fix for 7148289: [macosx] Deadlock in sun.lwawt.macosx.CWrapper$NSScreen.visibleFrame

[Alexander Zuev]

Hello,

   please review my fix for the CR 7148289: [macosx] Deadlock in 
sun.lwawt.macosx.CWrapper$NSScreen.visibleFrame

   Bug description is 
http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7148289

   Fix can be found at http://cr.openjdk.java.net/~kizune/7148289/webrev.00

With best regards,
Alex