@ToT m60 (and for a long time), 'dumpsys SurfaceFlinger' shows the ChromeTabbedActivity surface and the CompositorView with full-screen visible rects.  this may waste power during SF composition.

SurfaceFlinger is probably reading from the entire app surface every frame, even if it's mostly blank.  normally, what happens is that android shrinks the visible rect to the size of the views that are outside of the transparent region, or z-ordered above the SurfaceView in the the view heirarchy.  then, SF can ignore large parts of them during composition.  if the entire app surface is in the transparent region, then it's removed entirely from SF composition.

hierarchyviewer shows that there are some views hanging around in the tabbed activity that are probably preventing this behavior.

more docs here: https://docs.google.com/a/google.com/document/d/1rH9qQh3o2RIjbNfYMQ-1_-nXyQHg0gWwGHZWOChP9kw/edit?usp=sharing