Merge to XFA: Cleanup CJBig2_ArithDecoder.

TBR=tsepez@chromium.org

Review URL: https://codereview.chromium.org/1368153003 .

(cherry picked from commit 0fef7dd405ac85660dbeddd2e47620daffa70cb5)

Review URL: https://codereview.chromium.org/1381633003 .
2 files changed