NSS's filesystem speed detection doesn't work with the latest versions of sqlite, such as 3.6.22.  Set the NSS_SDB_USE_CACHE environment variable to "yes" to override NSS's detection if the database is on NFS.
NSS's filesystem speed detection doesn't work with the latest versions
of sqlite, such as 3.6.22.  Set the NSS_SDB_USE_CACHE environment
variable to "yes" to override NSS's detection if the database is on NFS.

Get rid of the USE_NSS_FOR_SSL_ONLY macro because it is simply the
opposite of USE_NSS.

Use EnvVarGetter to get and set environment variables.  Use FilePath
instead of std::string to represent path names.

R=thestig
BUG=48585
TEST=Run Chrome on Ubuntu Lucid with a home directory on "slow" NFS.
HTTPS connection setup shoud not be very slow.
Review URL: http://codereview.chromium.org/2895015

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@52379 0039d316-1c4b-4281-b951-d872f2087c98

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