remove unused SkFixed and SkFract functions

BUG=
R=caryclark@google.com

Review URL: https://codereview.chromium.org/113873008

git-svn-id: http://skia.googlecode.com/svn/trunk@12767 2bbb7eff-a529-9590-31e7-b0007b416f81
16 files changed