[9] Code Review Request For 8157295: Encapsulate impl_ methods in Scene and KeyValue classes

[Chien Yang]

Hi Jonathan and Kevin,

Please review the proposed fix:

Webrev: https://bugs.openjdk.java.net/browse/JDK-8157295
JIRA: http://cr.openjdk.java.net/~ckyang/JDK-8157295/webrev.00/

Thanks,
- Chien