Review for minimize on GTK.

[David Hill]

Kevin, et al,

(Note this fixed a regression post 8u20)

jira: https://javafx-jira.kenai.com/browse/RT-40261
webrev: http://cr.openjdk.java.net/~ddhill/T-40261

We tell the WindowManager not to support minimization (meaning the window decoration), then we ask it to minimize programmatically. The WM ignores the programmatic request because we just told it too.
The screen stops updating because the pulse thinks the window is not showing.

Simple fix - remember the window manager functions, and if minimize is not present, enable it, minimize the window, then restore the original value.

Tested with transparent & decorated. FullScreen also tested because that is something else we disable, but no negative effect seen.

-- 
David Hill<David.Hill at Oracle.com>
Java Embedded Development

"A man's feet should be planted in his country, but his eyes should survey the world."
-- George Santayana (1863 - 1952)