ref: a8a6f86e5827435b0afd8afb89c04e3dab46628a
parent: a0944ba19fb4969fc6b3a55c7189a482a9cd3e4f
author: Angie Chiang <angiebird@google.com>
date: Tue Feb 12 13:58:07 EST 2019
Add rd_diff_arr to store future blocks' rd diff Change-Id: Id996c1a427fb22a32b7a521cadf9f1523e5cf068