Extract LRUCache into generic cache type.
Extract LRUCache into generic cache type.

Change-Id: I402da4de408a44457daeec7497d2393c5f65ab66

prometheus/prometheus,jmcfarlane/prometheus,adamron1/prometheus,Conorbro/prometheus,gottwald/prometheus,GoogleCloudPlatform/prometheus,mtanda/prometheus,kzittritsch/prometheus,laushinka/prometheus,iksaif/prometheus,trigrass2/prometheus,abhishekamralkar/prometheus,prasincs/prometheus,jimmidyson/prometheus,brancz/prometheus,dln/prometheus,jbdalido/prometheus,prasincs/prometheus,tomwilkie/prometheus,PrFalken/prometheus,laushinka/prometheus,alileza/prometheus,ton31337/prometheus,jmcfarlane/prometheus,dsymonds/prometheus,AlekSi/prometheus,fabxc/prometheus,Gouthamve/prometheus,kzittritsch/prometheus,msiebuhr/prometheus,dmilstein/prometheus,mrwacky42/prometheus,smyrman/prometheus,dpatel06/prometheus,gcnonato/prometheus,trigrass2/prometheus,datajet-io/prometheus,dln/prometheus,eliothedeman/prometheus,mtanda/prometheus,robbiet480/prometheus,Conorbro/prometheus,jmcfarlane/prometheus,gcnonato/prometheus,jimmidyson/prometheus,nicr9/prometheus,jmcfarlane/prometheus,nicr9/prometheus,jbdalido/prometheus,gottwald/prometheus,hustbill/prometheus,abhishekamralkar/prometheus,wxdublin/prometheus,bluecmd/prometheus,dmilstein/prometheus,rajthilakmca/prometheus,alileza/prometheus,yanghongkjxy/prometheus,q3k/prometheus,gcnonato/prometheus,dsymonds/prometheus,sudhi-vm/prometheus,thachmai/prometheus,yanghongkjxy/prometheus,gesellix/prometheus,amorken/prometheus,Gouthamve/prometheus,thachmai/prometheus,wrouesnel/prometheus,ton31337/prometheus,wxdublin/prometheus,fabric8io/prometheus,abhishekamralkar/prometheus,JavierZunzunegui/prometheus,brancz/prometheus,tomwilkie/prometheus,cit-lab/prometheus,SaltedMan/prometheus-annotated,bluecmd/prometheus,robbiet480/prometheus,ton31337/prometheus,q3k/prometheus,Dieterbe/prometheus,agaoglu/prometheus,iksaif/prometheus,iksaif/prometheus,agaoglu/prometheus,brian-brazil/prometheus,robbiet480/prometheus,bluecmd/prometheus,GoogleCloudPlatform/prometheus,wndhydrnt/prometheus,kangwoo/prometheus,kzittritsch/prometheus,gesellix/prometheus,adamron1/prometheus,yanghongkjxy/prometheus,prometheus/prometheus,Colstuwjx/prometheus,smyrman/prometheus,SaltedMan/prometheus-annotated,SaltedMan/prometheus-annotated,alileza/prometheus,SaltedMan/prometheus-annotated,rajthilakmca/prometheus,dalanlan/prometheus,Gouthamve/prometheus,iksaif/prometheus,adamron1/prometheus,slok/prometheus,Colstuwjx/prometheus,smyrman/prometheus,alileza/prometheus,prometheus/prometheus,thachmai/prometheus,datajet-io/prometheus,slok/prometheus,RobertKielty/prometheus,brian-brazil/prometheus,Colstuwjx/prometheus,kangwoo/prometheus,slok/prometheus,tattsun/prometheus,q3k/prometheus,wrouesnel/prometheus,Conorbro/prometheus,abhishekamralkar/prometheus,JavierZunzunegui/prometheus,msiebuhr/prometheus,fabric8io/prometheus,RobertKielty/prometheus,agaoglu/prometheus,alileza/prometheus,Stackdriver/stackdriver-prometheus,thachmai/prometheus,Stackdriver/stackdriver-prometheus,cit-lab/prometheus,eliothedeman/prometheus,kangwoo/prometheus,gottwald/prometheus,msiebuhr/prometheus,adamron1/prometheus,amorken/prometheus,msiebuhr/prometheus,tomwilkie/prometheus,PrFalken/prometheus,keegancsmith/prometheus,fabric8io/prometheus,mrwacky42/prometheus,trigrass2/prometheus,JavierZunzunegui/prometheus,RobertKielty/prometheus,PrFalken/prometheus,GoogleCloudPlatform/prometheus,jbdalido/prometheus,wrouesnel/prometheus,dalanlan/prometheus,slok/prometheus,JavierZunzunegui/prometheus,rajthilakmca/prometheus,prasincs/prometheus,gottwald/prometheus,prasincs/prometheus,AlekSi/prometheus,robbiet480/prometheus,cit-lab/prometheus,mrwacky42/prometheus,fabxc/prometheus,flier/prometheus,tattsun/prometheus,dmilstein/prometheus,eliothedeman/prometheus,GoogleCloudPlatform/prometheus,Conorbro/prometheus,hustbill/prometheus,laushinka/prometheus,justintung/prometheus,brancz/prometheus,GoogleCloudPlatform/prometheus,mtanda/prometheus,dsymonds/prometheus,jimmidyson/prometheus,AlekSi/prometheus,q3k/prometheus,datajet-io/prometheus,Stackdriver/stackdriver-prometheus,kangwoo/prometheus,Stackdriver/stackdriver-prometheus,wxdublin/prometheus,sudhi-vm/prometheus,dpatel06/prometheus,dsymonds/prometheus,brancz/prometheus,kzittritsch/prometheus,tattsun/prometheus,tomwilkie/prometheus,wndhydrnt/prometheus,brian-brazil/prometheus,bluecmd/prometheus,dalanlan/prometheus,dln/prometheus,dmilstein/prometheus,dpatel06/prometheus,Gouthamve/prometheus,AlekSi/prometheus,dln/prometheus,laushinka/prometheus,flier/prometheus,gesellix/prometheus,wndhydrnt/prometheus,jbdalido/prometheus,eliothedeman/prometheus,prometheus/prometheus,hustbill/prometheus,smyrman/prometheus,wrouesnel/prometheus,flier/prometheus,sudhi-vm/prometheus,amorken/prometheus,yanghongkjxy/prometheus,datajet-io/prometheus,amorken/prometheus,Colstuwjx/prometheus,keegancsmith/prometheus,Dieterbe/prometheus,prometheus/prometheus,sudhi-vm/prometheus,justintung/prometheus,ton31337/prometheus,tattsun/prometheus,fabxc/prometheus,gcnonato/prometheus,rajthilakmca/prometheus,hustbill/prometheus,cit-lab/prometheus,fabric8io/prometheus,RobertKielty/prometheus,gesellix/prometheus,justintung/prometheus,keegancsmith/prometheus,mtanda/prometheus,Dieterbe/prometheus,justintung/prometheus,keegancsmith/prometheus,nicr9/prometheus,keegancsmith/prometheus,agaoglu/prometheus,fabxc/prometheus,PrFalken/prometheus,trigrass2/prometheus