Revert 121044 - Don't use system libpng by default. It causes security maintenance problems for ChromeOS. It's worth noting that we also don't use the system library for many other important components such as libxml.
Revert 121044 - Don't use system libpng by default. It causes security maintenance problems
for ChromeOS. It's worth noting that we also don't use the system library
for many other important components such as libxml.

Reverting due to compile errors on Linux:
http://chromegw.corp.google.com/i/chromium/builders/Linux%20Builder%20%28dbg%29%28shared%29/builds/17665/steps/compile/logs/stdio

BUG=112822

Review URL: http://codereview.chromium.org/9365007

TBR=cevans@chromium.org
Review URL: https://chromiumcodereview.appspot.com/9374001

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@121090 0039d316-1c4b-4281-b951-d872f2087c98

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