RFR: JDK-8059893 - Missing dio javadocs file

[Jen Dority]

issue: https://bugs.openjdk.java.net/browse/JDK-8059893
webrev: http://cr.openjdk.java.net/~jld/8059893/

Need a review for a webrev to add a file that was missing from a 
previous changeset.

Thanks,
Jen