[8] Review request for 7124244: [macosx] Shaped windows support

[Sergey Bylokhov]

Hi Everyone,
Please review the fix.

Shaped window was implemented as a translucent window with constrained 
graphics. Now translucent window doesn't use separate BufferedImage as a 
back buffer. Also alpha value for the swing back buffer was 
enabled(Shared code changed).
Note that shaped windows are affected by this bugs:
http://monaco.us.oracle.com/detail.jsf?cr=7124236
  - Shadows disappear.
  - Transparent areas aren't transparent to mouse clicks.
http://monaco.sfbay.sun.com/detail.jsf?cr=7172431
  - Opacity does not work for non opaque windows.

Any suggestions are welcome.

Bug: http://bugs.sun.com/bugdatabase/view_bug.do?bug_id=7124244
Webrev can be found at: http://cr.openjdk.java.net/~serb/7124244/webrev.00

-- 
Best regards, Sergey.