Code review comment for lp:~kdub/mir/post-if-optimizable

> What if some of the renderables in the list can be rendered with optimization
> and others cannot? AFAICT from the description
> post_renderables_if_optimizable() is all or nothing (although it doesn't need
> to be), so we would miss the opportunity to render some of the renderables
> more efficiently.

So, we touched on this in this in the standup, but we were worried about the Nested communication of this list when we go to enable Nested optimizations (we don't want to have the render negotiated with IPC). If the DisplayBuffer wants to optimize any one of the renderables, will have to handle the list, which works for mesa or android.