Implement par of aura menu spec: Disbled icon opacity: 0.5.
Implement par of aura menu spec:
Disbled icon opacity: 0.5.

http://www.corp.google.com/~kenmoore/mocks/chromeos/Misc_2012/Menus/markup1/menu4.html

BUG=122858
TEST=Disabled menu item icon should look half opaque.

Review URL: https://chromiumcodereview.appspot.com/10310064

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@135954 0039d316-1c4b-4281-b951-d872f2087c98

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