[cros] Cleanup boot times metrics.
[cros] Cleanup boot times metrics.

Boot time metric send_to_uma=true means reporting time since previous marker which is useless for these markers as it is always around few ms.

BootTime.Login is already reported, addet to histograms.xml:
https://chromereviews.googleplex.com/4459030/

BUG=127213
TEST=N/A


Review URL: https://chromiumcodereview.appspot.com/10310122

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@136759 0039d316-1c4b-4281-b951-d872f2087c98

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