Fix dependency on scoped_ptr::reset sequencing in ProxyResolverV8Tracing
Fix dependency on scoped_ptr::reset sequencing in ProxyResolverV8Tracing

scoped_ptr<T>::reset() currently guarantees that it deletes the old
stored pointer before assigning its argument to the stored pointer.
This is unsafe, because getting the deleter may result in the
destruction of the scoped_ptr<T> itself. unique_ptr<T> addresses this by
assigning its argument to the stored pointer before deleting the old
value of the stored pointer.

Unfortunately, this breaks code that assumes that the value of the
scoped_ptr will not change during scoped_ptr::reset() before destruction
of the old value is complete.

BUG=176091

Review URL: https://codereview.chromium.org/12261020

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@182541 0039d316-1c4b-4281-b951-d872f2087c98

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