Make JavaScript alert and confirm dialog boxes driveable by keyboard.
Make JavaScript alert and confirm dialog boxes driveable by keyboard.

This regressed in r60785. An error during refactoring used
-[JavaScriptAppModalDialogHelper textField] to determine whether an accessory
view was added to a JavaScript dialog box, but this isn't a simple getter, and
was allays returning true.

BUG=58299
TEST=- javascript:alert("x") allows return keypress to dismiss dialog (OK);
       if FKA is on, allows space bar operation
     - javascript:confirm("x") allows return keypress to dismiss dialog (OK);
       if FKA is on, has focus on Cancel, is tabbable between Cancel and OK,
       and allows space bar operation;
     - javascript:prompt("x") focuses text field and allows return keypress to
       dismiss dialog (OK);
       if FKA is on, is tabbable between text field and buttons, and allows
       space bar operation on buttons
     - Note: FKA is Full Keyboard Access, from System Preferences:Keyboard
Review URL: http://codereview.chromium.org/3555021

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@61847 0039d316-1c4b-4281-b951-d872f2087c98

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