Don't hold the lock when calling VideoRendererBase::OnFrameAvailable().
Don't hold the lock when calling VideoRendererBase::OnFrameAvailable().

There's one instance of the code where we hold on to the lock when calling OnFrameAvailable(), which means if the subclass can crash if it calls a locked method such as GetCurrentFrame().

BUG=none
TEST=media_unittests

Review URL: http://codereview.chromium.org/6260052

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@73362 0039d316-1c4b-4281-b951-d872f2087c98

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