Modify allocator to use malloc for the realloc(0, size) case. This works around webkit sensitivity to allocators that return  zero in this case.
Modify allocator to use malloc for the realloc(0, size) case.
This works around webkit sensitivity to allocators that return 
zero in this case.

BUG=20200
TEST=none

Review URL: http://codereview.chromium.org/302005

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@29425 0039d316-1c4b-4281-b951-d872f2087c98

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