A quick fix for Issue 13443 (Take 2).
A quick fix for Issue 13443 (Take 2).

It seems NXClient sends GDK_Tab not only when we press control+tab keys but also when we press control+shift+tab keys.
To emulate Firefox, this change checks if |modifier| is control+shift when |keyval| is either GDK_Tab, GDK_ISO_Left_Tab, or GDK_KP_Tab.

BUG=13443 "Shift+Ctrl+Tab should cycle tabs backwards"
TEST=Execute Chromium on an NX Client, press control+shift+tab keys, and verify tabs cycle backwards.
Review URL: http://codereview.chromium.org/155564

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@21944 0039d316-1c4b-4281-b951-d872f2087c98

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