Reconciles the following commits from aom/master to nextgenv2:
- 25aaf40bbc24beeb52de9af7d7624b7d7c6ce9de
- 87073de5693df70eba1c9b9be2b2732ed3b08fb3
Change-Id: Ideda50a6ec75485cb4fa7437c69f4e58d6a2ca73
This helps in porting entropy coder changes that happened in aom/master.
Change-Id: If423eeb3da552066cceb88227138ea61d6a20f07
(cherry picked from aom/master commit d311d02da55433d20aad6dd88e0bbb992919988d)