This CL continues the work began by CL #119958, extending it
to ScreenshareLayers.
Bug: webrtc:10249
Change-Id: I59d0c062a93b288007977e00aa3a2e0929509e0c
Reviewed-on: https://webrtc-review.googlesource.com/c/120042
Reviewed-by: Erik Språng <sprang@webrtc.org>
Commit-Queue: Elad Alon <eladalon@webrtc.org>
Cr-Commit-Position: refs/heads/master@{#26526}