Make browser_tests shardable.
Make browser_tests shardable.

Add methods to browser_tests which allow sharding
control to be used to select the tests that are
called by RunTest().  The same basic process is
used by GTest to decide if a given test should be
run (assuming the suite should be sharded).

Reuse GTEST_TOTAL_SHARDS and GTEST_SHARD_INDEX since
browser_tests is a wrapper around GTest and using the
same variable names will simplify our tools.

BUG=69423
TEST=browser_tests runs fine unsharded, can be run
sharded

Review URL: http://codereview.chromium.org/6333004

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@71530 0039d316-1c4b-4281-b951-d872f2087c98

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