Adds corner rounding capability in ViewRootImpl

This registers a callback with SurfaceFlinger to receive
the computed corner radii for the view. Also, adds ability
to ThreadedRenderer for clipping the corners

Bug: 372620947
Flag:com.android.graphics.surfaceflinger.flags.set_client_drawn_corner_radii
Test: presubmit; manual

Change-Id: I451e113c54d1b925d91430cd55326b770982d825