The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/9279a242c8866513526d9dde535b075723c99b07

commit 9279a242c8866513526d9dde535b075723c99b07
Author: Peng Huang <penghuang@chromium.org>
Date: Tue Dec 12 04:59:39 2017

ARC: fix the arc video playback with --mus

With recent changes, --mus has a separate viz process wich is launched by
browser process via GpuPorcessHost. So we should use GpuProcessHost to
request ARC related interfaces in Viz.

Bug:  793901 
Change-Id: Idd27f95fcf962b54634876024d0da4600da3f3aa
Reviewed-on: https://chromium-review.googlesource.com/820151
Reviewed-by: Yusuke Sato <yusukes@chromium.org>
Reviewed-by: Sadrul Chowdhury <sadrul@chromium.org>
Commit-Queue: Peng Huang <penghuang@chromium.org>
Cr-Commit-Position: refs/heads/master@{#523338}
[modify] https://crrev.com/9279a242c8866513526d9dde535b075723c99b07/chrome/browser/chromeos/arc/video/gpu_arc_video_service_host.cc