[Mac] Fix dragging of PDFs to tabstrip
[Mac] Fix dragging of PDFs to tabstrip

Relying on net::IsSupportedMimeType() does not account for plugins that can handle mime types. This change makes |IsSupportedFileURL()| query loaded plugins to check if the type is supported.

BUG=86855
TEST=Case 1: Enable PDF plugin. Drag PDF file from Finder to tabstrip. Dropping should be possible to open the PDF. Case 2: Disable PDF plugin. Drag PDF file from Finder to tabstrip. Dropping should not be possible.

Review URL: http://codereview.chromium.org/7222002

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@89851 0039d316-1c4b-4281-b951-d872f2087c98

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