Workaround for Issue 15949: cannot use the "WenQuanYi Bitmap Song" (chinese Fonts) as the system fonts with chrome
Workaround for Issue 15949: cannot use the "WenQuanYi Bitmap Song" (chinese Fonts) as the system fonts with chrome

- Adding a font fallback code to Font::CreateFont() in font_skia.cc so that Chromium can startup even when a non-scalable font is selected as an application font. If the application font is non-scalable, Font::CreateFont() loads a _scalable_ "sans" font as a fallback.
  (Note: The function still never load non-scalable fonts.)
- Removed a comment for issue 12530 since the issue has been fixed.

BUG=12530
BUG=15949
TEST=Download the snap.pcf font from http://artwizaleczapka.sourceforge.net/ and put it to ~/.fonts/. Remove temporarily /etc/fonts/conf.d/70-no-bitmaps.conf and run "fc-cache -f". Start /ust/bin/gnome-appearance-properties and select "snap" as your application font. Then start chromium and verify that it does not crash (by the CHECK failure) on startup.

Review URL: http://codereview.chromium.org/207009

git-svn-id: de016e52bd170d2d4f2344f9bf92d50478b649e0@26652 0039d316-1c4b-4281-b951-d872f2087c98

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