RFR:

[Erik Helin]

Hi all,

this small patch removes the class OopsInHeapRegionClosure. 
OopsInHeapRegionClosure only contains a protected _from field and the 
public method set_from, and there are only two other classes inheriting 
from OopsInHeapRegionClosure (G1ScanClosureBase and UpdareRsetDeferred).

This patch gets rid of the class OopsInHeapRegionClosure and adds the 
corresponding field and method to the classes inheriting from 
OopsInHeapRegionClosure.

Patch: http://cr.openjdk.java.net/~ehelin/8183124/00/

Bug: https://bugs.openjdk.java.net/browse/JDK-8183124

Testing: make jprt

Thanks,
Erik