If $\displaystyle \int_{-3}^{0} f(x) \: dx = 5$ and $\displaystyle \int_{-3}^{1} g(x) \: dx = 0$, what is the value of $\displaystyle \int\!\!\int_{D} f(x)\!g(y) \: dA$ where $D$ is the rectangle: $-3 \leq x \leq 0, \ \ -3 \leq y \leq 1$?