Size the buffer used for the metrics log text properly.
Size the buffer used for the metrics log text properly.

The existing code was abusing the WriteInto interface (base/string_util.h).
The size passed to WriteInto should be the size of the string plus one for
a terminating NUL byte.

This bug caused the final newline in the log to be clipped.  c_str users
(there probably weren't any) would see the final newline which wouldn't be
wouldn't be followed by a NUL byte.

TEST=not really any
BUG=21733
Review URL: http://codereview.chromium.org/194099

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@26280 0039d316-1c4b-4281-b951-d872f2087c98

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