add virtual SkTypeface::onOpenStream and override that for fontconfig
(other ports to follow)

When this is complete, we will be able to remove from SkFontHost
- OpenStream
- GetFileName
Review URL: https://codereview.chromium.org/12988002

git-svn-id: http://skia.googlecode.com/svn/trunk@8299 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed