[8] Request for review: 8017189 [macosx] AWT program menu disabled on Mac

[Sergey Bylokhov]

Hello,
Please review the fix for jdk 8 and 7u40.
The fix for JDK-8010906 don't take into account situation then first 
parent has no menu bar, but the second has.
So it introduce the next scenario:
#1. Open the window with File menu.
#2. Open modal dialog1 =>File menu is disabled
#3. Open modal dialog2 =>File menu disappears
#4. Close dialog two
#5. Close dialog one. File menu reappears, but File still disabled

The steps #3. occurred, because CMenuBar.activate resets the current 
menubar if a passed javaMenuBar is null.
The steps #5. occurred, because at step #3 we do not remove our nsmenu 
from the deleted NSMenuItem, when the appropriate NSMenuItem removed 
from mainMenu. So at step #5 we got a situation, when our nsmenu was 
added to the two different nsmenuitems: old(disabled) and new(enabled).

Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=8017189
Webrev can be found at: http://cr.openjdk.java.net/~serb/8017189/webrev.00

-- 
Best regards, Sergey.