This speeds up decode for a 720p workload from 25s to 5s on my machine. I did some benchmarking and it appears we spend the vast majority of the time on zxing decoding, so now we will bring all processors on the the machine to bear. BUG=webrtc:4986 Review URL: https://codereview.webrtc.org/1428433002 Cr-Commit-Position: refs/heads/master@{#10443}