Review request for 7124430: [macosx] LWCToolkit.grab() and LWCToolkit.ungrab() events are not implemented yet

[Anton V. Tarasov]

Hello,

Please review a fix for 7124430.

webrev: http://cr.openjdk.java.net/~ant/7124430/webrev.1/

UngrabEvent dispatching is implemented according to the cases mentioned
in the UngrabEvent class description, except for the case of clicking
in an owner frame's title. The latter, as I found, can't be implemented
on Mac OS X platform. Along with the implementation, a regression test
is proposed.

Thanks,
Anton.