Crash fix: TabContents are destroyed while SavePackage active.
Crash fix: TabContents are destroyed while SavePackage active.

Typically the TabContents holds the only reference to the SavePackage
it creates.

However, during the
GetSaveInfo->CreateDirectoryOnFileThread->ContinueGetSaveInfo
sequence, additional references to the SavePackage are held via the
CancelableTask's created by NewRunnableMethod.

BUG=70145
TEST=None


Review URL: http://codereview.chromium.org/6834045

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@81586 0039d316-1c4b-4281-b951-d872f2087c98

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