For power saving on Chromecast Ultra, want to restrict scanout to subset of graphics plane with content. Rough steps:
* Use swap buffers with damage API for now (although it's semantically different, so should consider a new EGL extension instead)
* Create SwapWithBounds API for passing bounds through to GPU process at swap time
* Compute content bounds in compositor/overlay code (i.e. bounds of non-overlay content) and pass through when swapping
Comment 1 by bugdroid1@chromium.org
, Feb 6 2017