Explicitly empty the pipes on teardown to prevent cross process races.
Explicitly empty the pipes on teardown to prevent cross process races.

When running with --use-gl=osmesa on desktop linux builds, it's important to XSync in GPU process before firing an IPC to the browser in ~GpuCommandBufferStub. Otherwise, there may be X commands for the window pending when the browser destroys the associated X window.

BUG=155834

Review URL: https://chromiumcodereview.appspot.com/11230036

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@163431 0039d316-1c4b-4281-b951-d872f2087c98

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