add charsToGlyphs to SkTypeface

Will disable new unittest until all backends are implemented.

On Mac, new API is 4x faster than old paint one, so next CL I will reimplement the paint calls in terms of the new typeface call.

R=eae@chromium.org

Review URL: https://codereview.chromium.org/18083023

git-svn-id: http://skia.googlecode.com/svn/trunk@9860 2bbb7eff-a529-9590-31e7-b0007b416f81
6 files changed