Revert 175826
Revert 175826

This change appears to be breaking the ChromeOS(x86) and ChromeOS(amd64) bots.
http://build.chromium.org/p/chromium.chromiumos/builders/ChromiumOS%20%28x86%29/builds/11010

> Clean up: remove unnecessary if-branches on initialization of the a11y prefs.
> 
> According to the comment at preferences.cc:96, some accessibility prefs may be already registered in WizardController::RegisterPrefs. But the magnifier prefs are never registered there, hence we can remove if statements.
> 
> BUG=none
> TEST=launch ChromeOS, and login.
> 
> Review URL: https://chromiumcodereview.appspot.com/11820018

TBR=yoshiki@chromium.org
Review URL: https://codereview.chromium.org/11817029

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@175871 0039d316-1c4b-4281-b951-d872f2087c98

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