Currently the state of shapes, etc, is shadowed in the PG scene graph which computes a new bounds in response to changes in the FX scene graph. This is inefficient. Instead, we plan to move the responsibility for bounds computation to the FX scene graph to allow us to be more lazy in computing bounds. We still need utilities in the PG layer to assist with computing the bounds, but calling these utility functions will be under the control of the FX scene graph.