Debug crash in WebstoreInstaller::StartDownload()
Debug crash in WebstoreInstaller::StartDownload()

WebstoreInstaller is RefCounted, so there's no reason to make it base::Unretained, which just opens up a deletion race, or appears to.
controller_ may be NULL. NavigationController::GetActiveEntry() may be NULL.

This crash has persisted at a low, not quite dismissible frequency for a long time.

BUG=126013

Review URL: https://chromiumcodereview.appspot.com/10453039

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@141771 0039d316-1c4b-4281-b951-d872f2087c98

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