Fix a stack overflow crash in the accessibility code in the renderer. The crash occurs in the  RendererAccessibility::PostAccessibilityNotification function while processing the WebAccessibilityNotificationLayoutComplete  notification from webkit. This function recursively calls itself with the WebAccessibilityNotificationLayoutComplete notification leading to infinite recursion.
Fix a stack overflow crash in the accessibility code in the renderer. The crash occurs in the 
RendererAccessibility::PostAccessibilityNotification function while processing the WebAccessibilityNotificationLayoutComplete 
notification from webkit. This function recursively calls itself with the WebAccessibilityNotificationLayoutComplete
notification leading to infinite recursion.

Fix is to check whether the incoming notification is WebAccessibilityNotificationLayoutComplete before the recursive
call.

BUG=none
TEST=chrome frame tests should pass on the IE6 builder.
Review URL: http://codereview.chromium.org/8952005

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@114573 0039d316-1c4b-4281-b951-d872f2087c98

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