On Chrome OS, we have a ash::VideoDetector running in the browser process that detects whether a renderer is likely playing a video and consequently notifies the power manager to prevent the screen from turning off, the Chromebook from suspending, etc. This is currently doable because the browser process receives renderers' CompositorFrames, but eventually they will bypass the browser process and go directly to Viz. We should implement the video detector in Viz and notify ash::VideoDetector via a mojo interface in order to make it compatible with Viz.
Comment 1 by fsamuel@google.com
, Oct 18 2017