<Swing Dev> [13] Review Request: 8177960 Deprecate the Swing Motif Look and Feel and document it as unsupported on macOS

[Sergey Bylokhov]

Hello.
Please review the fix for JDK 13.

Bug: https://bugs.openjdk.java.net/browse/JDK-8177960
CSR: https://bugs.openjdk.java.net/browse/JDK-8218637
Fix: http://cr.openjdk.java.net/~serb/8177960/webrev.01

This is a request to deprecate the Swing Motif Look and Feel,
and document it as unsupported on macOS platform in JDK 13.

The Motif L&F has long been part of the Swing implementation
shipped with the JDK, although unlike L&Fs such as Metal and
Nimbus it is not exposed in Java APIs and not part of the Java SE specification.

This look and feel was implemented as the System look and feel for the
Solaris platform at time when the CDE/Motif environment was used the
principal supported desktop environment. But it was placed in shared code
and provided and supported on all platforms including Windows and later macOS.

Since it is superseded as a system L&F by the GTK L&F and has limited use and
additionally as a L&F is very dated visually, we would like to discourage further use.

Note in some future release we may remove it completely, or we may remove
it from the shared code to stop distributing it on Windows and macOS.
These are mentioned here to give the most possible notice of such
possible additional changes.

-- 
Best regards, Sergey.