DO NOT MERGE | libvpx: cherry-pick aa1c813 from upstream am: 909f63f1b2  -s ours am: 3454a26543 am: 701ffecc8b am: f01595fd69  -s ours am: d04db41907 am: bd8d238da3 am: 1eeb87d66d
am: c2403db46c  -s ours

Change-Id: Ia18cc4ae43c09572c9c16d8c8d670cf5f63a5bea