Continue ChromeToMobileService::RequestSearch if previous_search_time_.is_null.
Continue ChromeToMobileService::RequestSearch if previous_search_time_.is_null.

My crrev.com/127780 mistakenly uses a null last_search_time.
So the first legit call to ChromeToMobileService::RequestSearch may bail.

TBR=sky
BUG=102709
TEST=Chrome To Mobile icon appears, even when you've started your computer in the last 24 hours :p

Review URL: http://codereview.chromium.org/9813002

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@127934 0039d316-1c4b-4281-b951-d872f2087c98

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