<Swing Dev> JDK 9 RFR of JDK-8035692 : Fix serial lint warnings in mac-specific code

[Joe Darcy]

Hello,

Please review this webrev which addresses serial warnings in 
mac-specific code:

     JDK-8035692 : Fix serial lint warnings in mac-specific code
     http://cr.openjdk.java.net/~darcy/8035692.0/

Thanks,

-Joe