Don't compile with TraceLog support on by default.
Don't compile with TraceLog support on by default.

This is just some experimental performance code.  Previously it was creating
a singleton object which created a ProcessMetrics object.  This caused a bunch
of possibly expensive calls to query system information to happen on startup.

Review URL: http://codereview.chromium.org/174118


git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@23819 0039d316-1c4b-4281-b951-d872f2087c98

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