RFR (S): 8226232: Move merge heap roots code out from G1RemSetScanState

[Kim Barrett]

> On Jul 10, 2019, at 11:30 AM, Thomas Schatzl <thomas.schatzl at oracle.com> wrote:
> 
> Hi all,
> 
>  can I have reviews for this small change that moves code related to
> the merge heap roots phase out of G1RemSetScanState? This imho
> significantly increases readability of G1RemSetScanState.
> 
> More minor cleanups to improve the code are planned, but I think it is
> good to take it in steps.
> 
> CR:
> https://bugs.openjdk.java.net/browse/JDK-8226232
> Webrev:
> http://cr.openjdk.java.net/~tschatzl/8226232/webrev/
> Testing:
> hs-tier1-5
> 
> Thanks,
>  Thomas

Looks good.

One small item:

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src/hotspot/share/gc/g1/g1RemSet.cpp
1166   {
1167     _scan_state->prepare_for_merge_heap_roots();
1168   }

Leftover extra scope nesting?

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