Can the Galvanized Steel Water Rain Diverter Drip Edge Flashing be used to divert rain water from a chimney?

Though not typically used as you are suggesting it should work as long as the amount of water is not too great to overrun the lip.

When installed the water diverter flashing does catch and divert the water to run off each end rather than directly down the roof slope. Though not typically used as you are suggesting it should work as long as the amount of water is not too great to overrun the lip.