Revert "Provide a GPU implementation of SkArithmeticMode, using a custom GrEffect exposed via asNewEffectOrCoeff()."

This reverts commit b8ffe17b5c684f9cfff02285f27e6aa1f75c9b53.

TBR=robertphillips

Review URL: https://codereview.chromium.org/16115007

git-svn-id: http://skia.googlecode.com/svn/trunk@9325 2bbb7eff-a529-9590-31e7-b0007b416f81
4 files changed