ui/base/models: Avoid an unnecessary tmp variable in TreeNode::GetTotalNodeCount().
ui/base/models: Avoid an unnecessary tmp variable in TreeNode::GetTotalNodeCount().

Unrelated changes:
- Use the member variable |parent_| directly instead of calling the getter accessor |parent()|.
- Tweak some comments. Use node instead of Node to be more consistent.

BUG=None
TEST=out/Debug/app_unittests --gtest_filter=TreeNodeModelTest.GetTotalNodeCount

R=sky@chromium.org

Review URL: http://codereview.chromium.org/6975054

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@87481 0039d316-1c4b-4281-b951-d872f2087c98

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