<AWT Dev> [9] Review Request: JDK-8037560 [macosx] Cleaup CClipboard.m

[Petr Pchelko]

Hello, AWT Team.

The bug: https://bugs.openjdk.java.net/browse/JDK-8037560
The fix: http://cr.openjdk.java.net/~pchelko/9/8037560/webrev/

Recently I've tried to fix our clipboard tests and make a proper implementation of the ClipboardOwner notifications on Mac OS X. 
However this appeared to be impossible without any over-complex solution due to Cocoa restrictions. By the way I've done a big 
clean-up of the Clipboard native code which would be a pity to throw away. So could you please review this clean-up fix.

What I'm doing is replacing the selector-based invocations with block-based, so the source shrinks quite a lot.

With best regards. Petr.