RFR (S): 8213142: Use RAII to set the scanning source in G1ScanEvacuatedObjClosure

[Kim Barrett]

> On Oct 30, 2018, at 6:42 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi all,
> 
>  in the review for JDK-8212911 Kim suggested to use RAII to set the
> _scanning_in_young field of the G1ScanEvacuatedObjClosure class. This
> also allows making sure that the field is actually initialized when
> used.
> 
> This is the implementation for this idea.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8213142
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8213142/webrev/
> Testing:
> local gc jtreg run
> 
> Thanks,
>  Thomas

Looks good.