In certain situations, a developer may require the border of a Material to be painted behind its child. For example a Card widget that has a full width image across the top half. In that scenario, the image should ideally be painted above the border with regards to z-position.
This change exposes a flag on Material widget to achieve this behavior. Additionally, the same flag is exposed on Card widget to allow the Card widget to pass this down to its Material.
I added a couple golden tests to verify this new behavior. Goldens are here:
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