Set LCD font smoothing to "medium" for gm on Mac, regardless of system settings

http://code.google.com/p/skia/issues/detail?id=382 ('make gm results consistent regardless of system LCDtext settings')
Review URL: https://codereview.appspot.com/5661043

git-svn-id: http://skia.googlecode.com/svn/trunk@3184 2bbb7eff-a529-9590-31e7-b0007b416f81
5 files changed