[9] Code Review Request For 8155053: Encapsulate impl_ methods in Effect and on the setting of TraversalEngine

[Chien Yang]

Hi Kevin,

Please review the purposed fix.

JIRA: https://bugs.openjdk.java.net/browse/JDK-8155053
Webrev: http://cr.openjdk.java.net/~ckyang/JDK-8155053/webrev.00/

Thanks,
- Chien