Simpler version of Plus w/ AA.  ~25% faster too.
Simpler version of Plus w/ AA.  ~25% faster too.

BUG=skia:3852

TBR=fmalita@chromium.org

Review URL: https://codereview.chromium.org/1150693003

invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia,invisiblek/android_external_skia