[net/dns] Don't use memset to initialize a struct with string16 members.
[net/dns] Don't use memset to initialize a struct with string16 members.

Forcing string16 to 0 leads to iterator compatiblity check crash in MSVS2010 Debug builds.

This bug was diagnosed by tom.cassiotis@gmail.com

BUG=131589
TEST=Start MSVS2010 Debug build of chrome.exe

Review URL: https://chromiumcodereview.appspot.com/10545065

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@141213 0039d316-1c4b-4281-b951-d872f2087c98

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