ref: ecb03e9a3f5163a4ee7bc2aaae521d5c5be090d2
parent: 499fe05dc030b31d15c2ad9717e6bcee839f7d12
author: Yaowu Xu <yaowu@google.com>
date: Mon Feb 25 12:01:30 EST 2013
make cost_coeffs to use combined context Change-Id: Ia15f4244595fab49bffda0c651a750a8a9481d28