Disk cache: Close the current experiment for new users.
Disk cache: Close the current experiment for new users.

Intended for the Beta branch.
(this is a reland of 88690)

BUG=91040
TEST=none
TBR=gavinp@chromium.org
Review URL: http://codereview.chromium.org/7518006

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@94764 0039d316-1c4b-4281-b951-d872f2087c98

bright-sparks/chromium-spacewalk,rogerwang/chromium,timopulkkinen/BubbleFish,M4sse/chromium.src,markYoungH/chromium.src,junmin-zhu/chromium-rivertrail,krieger-od/nwjs_chromium.src,mohamed--abdel-maksoud/chromium.src,robclark/chromium,TheTypoMaster/chromium-crosswalk,bright-sparks/chromium-spacewalk,markYoungH/chromium.src,ChromiumWebApps/chromium,Chilledheart/chromium,Jonekee/chromium.src,hgl888/chromium-crosswalk,axinging/chromium-crosswalk,keishi/chromium,Just-D/chromium-1,junmin-zhu/chromium-rivertrail,littlstar/chromium.src,bright-sparks/chromium-spacewalk,nacl-webkit/chrome_deps,markYoungH/chromium.src,junmin-zhu/chromium-rivertrail,Pluto-tv/chromium-crosswalk,bright-sparks/chromium-spacewalk,krieger-od/nwjs_chromium.src,rogerwang/chromium,dushu1203/chromium.src,crosswalk-project/chromium-crosswalk-efl,anirudhSK/chromium,crosswalk-project/chromium-crosswalk-efl,hgl888/chromium-crosswalk,zcbenz/cefode-chromium,Jonekee/chromium.src,mohamed--abdel-maksoud/chromium.src,Jonekee/chromium.src,markYoungH/chromium.src,anirudhSK/chromium,Just-D/chromium-1,markYoungH/chromium.src,hujiajie/pa-chromium,axinging/chromium-crosswalk,axinging/chromium-crosswalk,Jonekee/chromium.src,ChromiumWebApps/chromium,nacl-webkit/chrome_deps,pozdnyakov/chromium-crosswalk,axinging/chromium-crosswalk,ChromiumWebApps/chromium,ondra-novak/chromium.src,keishi/chromium,Fireblend/chromium-crosswalk,hgl888/chromium-crosswalk-efl,rogerwang/chromium,fujunwei/chromium-crosswalk,Just-D/chromium-1,littlstar/chromium.src,krieger-od/nwjs_chromium.src,rogerwang/chromium,ltilve/chromium,TheTypoMaster/chromium-crosswalk,pozdnyakov/chromium-crosswalk,hujiajie/pa-chromium,hujiajie/pa-chromium,pozdnyakov/chromium-crosswalk,Fireblend/chromium-crosswalk,chuan9/chromium-crosswalk,hgl888/chromium-crosswalk,Pluto-tv/chromium-crosswalk,patrickm/chromium.src,ltilve/chromium,markYoungH/chromium.src,chuan9/chromium-crosswalk,pozdnyakov/chromium-crosswalk,anirudhSK/chromium,Just-D/chromium-1,pozdnyakov/chromium-crosswalk,chuan9/chromium-crosswalk,keishi/chromium,patrickm/chromium.src,Jonekee/chromium.src,M4sse/chromium.src,Jonekee/chromium.src,axinging/chromium-crosswalk,Fireblend/chromium-crosswalk,patrickm/chromium.src,rogerwang/chromium,mogoweb/chromium-crosswalk,bright-sparks/chromium-spacewalk,dednal/chromium.src,ChromiumWebApps/chromium,anirudhSK/chromium,hujiajie/pa-chromium,TheTypoMaster/chromium-crosswalk,patrickm/chromium.src,littlstar/chromium.src,M4sse/chromium.src,M4sse/chromium.src,zcbenz/cefode-chromium,markYoungH/chromium.src,anirudhSK/chromium,ChromiumWebApps/chromium,Pluto-tv/chromium-crosswalk,hujiajie/pa-chromium,rogerwang/chromium,pozdnyakov/chromium-crosswalk,ondra-novak/chromium.src,hujiajie/pa-chromium,krieger-od/nwjs_chromium.src,bright-sparks/chromium-spacewalk,anirudhSK/chromium,littlstar/chromium.src,mogoweb/chromium-crosswalk,timopulkkinen/BubbleFish,jaruba/chromium.src,markYoungH/chromium.src,keishi/chromium,hgl888/chromium-crosswalk,timopulkkinen/BubbleFish,axinging/chromium-crosswalk,chuan9/chromium-crosswalk,dushu1203/chromium.src,ltilve/chromium,dednal/chromium.src,M4sse/chromium.src,timopulkkinen/BubbleFish,Chilledheart/chromium,hgl888/chromium-crosswalk-efl,junmin-zhu/chromium-rivertrail,littlstar/chromium.src,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk-efl,dushu1203/chromium.src,dednal/chromium.src,crosswalk-project/chromium-crosswalk-efl,timopulkkinen/BubbleFish,TheTypoMaster/chromium-crosswalk,ondra-novak/chromium.src,Just-D/chromium-1,bright-sparks/chromium-spacewalk,TheTypoMaster/chromium-crosswalk,dushu1203/chromium.src,fujunwei/chromium-crosswalk,axinging/chromium-crosswalk,robclark/chromium,keishi/chromium,Fireblend/chromium-crosswalk,Pluto-tv/chromium-crosswalk,Jonekee/chromium.src,timopulkkinen/BubbleFish,dednal/chromium.src,krieger-od/nwjs_chromium.src,PeterWangIntel/chromium-crosswalk,nacl-webkit/chrome_deps,M4sse/chromium.src,junmin-zhu/chromium-rivertrail,dushu1203/chromium.src,hgl888/chromium-crosswalk-efl,rogerwang/chromium,littlstar/chromium.src,fujunwei/chromium-crosswalk,ltilve/chromium,zcbenz/cefode-chromium,patrickm/chromium.src,timopulkkinen/BubbleFish,Pluto-tv/chromium-crosswalk,dednal/chromium.src,fujunwei/chromium-crosswalk,anirudhSK/chromium,zcbenz/cefode-chromium,crosswalk-project/chromium-crosswalk-efl,nacl-webkit/chrome_deps,Chilledheart/chromium,bright-sparks/chromium-spacewalk,keishi/chromium,hgl888/chromium-crosswalk,hujiajie/pa-chromium,ondra-novak/chromium.src,chuan9/chromium-crosswalk,ondra-novak/chromium.src,nacl-webkit/chrome_deps,ChromiumWebApps/chromium,nacl-webkit/chrome_deps,jaruba/chromium.src,nacl-webkit/chrome_deps,rogerwang/chromium,mohamed--abdel-maksoud/chromium.src,jaruba/chromium.src,hujiajie/pa-chromium,Pluto-tv/chromium-crosswalk,keishi/chromium,Fireblend/chromium-crosswalk,ChromiumWebApps/chromium,Just-D/chromium-1,hujiajie/pa-chromium,mogoweb/chromium-crosswalk,chuan9/chromium-crosswalk,hujiajie/pa-chromium,patrickm/chromium.src,mogoweb/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,chuan9/chromium-crosswalk,timopulkkinen/BubbleFish,keishi/chromium,Fireblend/chromium-crosswalk,markYoungH/chromium.src,mohamed--abdel-maksoud/chromium.src,pozdnyakov/chromium-crosswalk,hgl888/chromium-crosswalk-efl,Pluto-tv/chromium-crosswalk,fujunwei/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,chuan9/chromium-crosswalk,M4sse/chromium.src,mohamed--abdel-maksoud/chromium.src,mohamed--abdel-maksoud/chromium.src,pozdnyakov/chromium-crosswalk,krieger-od/nwjs_chromium.src,ltilve/chromium,dushu1203/chromium.src,TheTypoMaster/chromium-crosswalk,hgl888/chromium-crosswalk-efl,fujunwei/chromium-crosswalk,nacl-webkit/chrome_deps,ChromiumWebApps/chromium,PeterWangIntel/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,anirudhSK/chromium,mogoweb/chromium-crosswalk,zcbenz/cefode-chromium,pozdnyakov/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,patrickm/chromium.src,rogerwang/chromium,Chilledheart/chromium,Jonekee/chromium.src,zcbenz/cefode-chromium,M4sse/chromium.src,dednal/chromium.src,littlstar/chromium.src,jaruba/chromium.src,hgl888/chromium-crosswalk,jaruba/chromium.src,dushu1203/chromium.src,axinging/chromium-crosswalk,mogoweb/chromium-crosswalk,hgl888/chromium-crosswalk-efl,anirudhSK/chromium,mohamed--abdel-maksoud/chromium.src,pozdnyakov/chromium-crosswalk,zcbenz/cefode-chromium,crosswalk-project/chromium-crosswalk-efl,Just-D/chromium-1,timopulkkinen/BubbleFish,Jonekee/chromium.src,Pluto-tv/chromium-crosswalk,timopulkkinen/BubbleFish,axinging/chromium-crosswalk,nacl-webkit/chrome_deps,dushu1203/chromium.src,dushu1203/chromium.src,Fireblend/chromium-crosswalk,robclark/chromium,mogoweb/chromium-crosswalk,hgl888/chromium-crosswalk-efl,mogoweb/chromium-crosswalk,fujunwei/chromium-crosswalk,patrickm/chromium.src,Chilledheart/chromium,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk-efl,Fireblend/chromium-crosswalk,M4sse/chromium.src,junmin-zhu/chromium-rivertrail,robclark/chromium,pozdnyakov/chromium-crosswalk,ChromiumWebApps/chromium,TheTypoMaster/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,dushu1203/chromium.src,ondra-novak/chromium.src,krieger-od/nwjs_chromium.src,robclark/chromium,krieger-od/nwjs_chromium.src,zcbenz/cefode-chromium,krieger-od/nwjs_chromium.src,Chilledheart/chromium,jaruba/chromium.src,robclark/chromium,ondra-novak/chromium.src,Fireblend/chromium-crosswalk,krieger-od/nwjs_chromium.src,anirudhSK/chromium,M4sse/chromium.src,crosswalk-project/chromium-crosswalk-efl,TheTypoMaster/chromium-crosswalk,junmin-zhu/chromium-rivertrail,rogerwang/chromium,jaruba/chromium.src,hujiajie/pa-chromium,krieger-od/nwjs_chromium.src,bright-sparks/chromium-spacewalk,ltilve/chromium,ltilve/chromium,Chilledheart/chromium,jaruba/chromium.src,mohamed--abdel-maksoud/chromium.src,junmin-zhu/chromium-rivertrail,robclark/chromium,junmin-zhu/chromium-rivertrail,anirudhSK/chromium,dednal/chromium.src,jaruba/chromium.src,Jonekee/chromium.src,jaruba/chromium.src,Chilledheart/chromium,ltilve/chromium,chuan9/chromium-crosswalk,PeterWangIntel/chromium-crosswalk,nacl-webkit/chrome_deps,mogoweb/chromium-crosswalk,jaruba/chromium.src,ltilve/chromium,ChromiumWebApps/chromium,robclark/chromium,ondra-novak/chromium.src,mogoweb/chromium-crosswalk,M4sse/chromium.src,zcbenz/cefode-chromium,PeterWangIntel/chromium-crosswalk,markYoungH/chromium.src,Just-D/chromium-1,junmin-zhu/chromium-rivertrail,zcbenz/cefode-chromium,nacl-webkit/chrome_deps,dednal/chromium.src,markYoungH/chromium.src,dednal/chromium.src,robclark/chromium,patrickm/chromium.src,axinging/chromium-crosswalk,mohamed--abdel-maksoud/chromium.src,Chilledheart/chromium,Pluto-tv/chromium-crosswalk,ChromiumWebApps/chromium,Just-D/chromium-1,keishi/chromium,keishi/chromium,dednal/chromium.src,keishi/chromium,PeterWangIntel/chromium-crosswalk,hgl888/chromium-crosswalk,Jonekee/chromium.src,axinging/chromium-crosswalk,dednal/chromium.src,dushu1203/chromium.src,ondra-novak/chromium.src,PeterWangIntel/chromium-crosswalk,littlstar/chromium.src,timopulkkinen/BubbleFish,fujunwei/chromium-crosswalk,hgl888/chromium-crosswalk,hgl888/chromium-crosswalk,robclark/chromium,anirudhSK/chromium,junmin-zhu/chromium-rivertrail,PeterWangIntel/chromium-crosswalk,crosswalk-project/chromium-crosswalk-efl,zcbenz/cefode-chromium,ChromiumWebApps/chromium,TheTypoMaster/chromium-crosswalk,hgl888/chromium-crosswalk-efl