CrOS - Speculative fix for shutdown hang talking to zygote
CrOS - Speculative fix for shutdown hang talking to zygote

ZygoteHost in the browser acquires a lock, sends fork requests to the zygote, then blocks on a read while waiting for a reply with the pid of the forked process.  In many error conditions, the zygote never sends a reply to the browser.  Now we send back an invalid pid (-1), which ZygoteHost already handles.

BUG=chromium-os:20825
TEST=Ensure you can open and close tabs normally.  After that, we'll have to watch crash reports.

Review URL: http://codereview.chromium.org/8062001

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@103467 0039d316-1c4b-4281-b951-d872f2087c98

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