Remove assertion on instance destruction.
Remove assertion on instance destruction.

The way that we do the wrappers now with InstanceHandles means there's no danger of dangling pointers, and actually that you can't unregister yourself during instance shutdown since the PP_Instance->pp::Instance mapping has been torn down by the time the instance destructor is called.

Review URL: https://chromiumcodereview.appspot.com/9519001

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@124119 0039d316-1c4b-4281-b951-d872f2087c98

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