In bug 806375 , we got CopyOutputRequests working when VIZ is enabled. However, this was for Layers, and only when the layer tree is in a privileged process.
Some callpoints, such as RenderWidgetHostViewChildFrame::SubmitSurfaceCopyRequest(), don't have a way to get at the privileged Layer in the browser process. So, we still need a true "copy from surface" API and impl for VIZ.
Note that content::DelegatedFrameHost currently makes Layer snapshots instead of Surface snapshots when VIZ is enabled. So, once we have the "copy from surface" API for VIZ, DFH should be updated to call into that instead.
Current thinking is to add a FrameSinkManager::TakeSnapshot() API alongside the existing FrameSinkManager::CreateVideoCapturer().
Comment 1 by bugdroid1@chromium.org
, Feb 14 2018