Adding libusb as a direct dependency of browser_extensions.
Adding libusb as a direct dependency of browser_extensions.

As reported by the Gentoo packagers in https://bugs.gentoo.org/413251 the
USE_SYSTEM_LIBUSB define doesn't get set when UsbDeviceResource is compiled as
part of the browser extensions.

BUG=124803
TEST=none


Review URL: https://chromiumcodereview.appspot.com/10389096

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@136946 0039d316-1c4b-4281-b951-d872f2087c98

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