Fix notification settings dialog visuals.
Fix notification settings dialog visuals.

This CL does the following things:
- do not shrink the contents of the scroll view, instead enlarge the
  window if there is a scroll bar.
- set an empty insets for separator, otherwise a scrollbar appears
  when the total height of the contents is exactly same as the expected
  window height.
- fix the length of the separator.

BUG=161094

Review URL: https://codereview.chromium.org/12566037

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@189289 0039d316-1c4b-4281-b951-d872f2087c98

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