Google maps - how to get building's polygon coordinates from address?

Question

How to implement the following:

1. User defines an address
2. User defines a color
3. Service searches for a corresponding building on the google map
4. Service fills the found building on the map with the color

I know how to:

1.find lat/long of the address

2.draw the polygon

So, to do the task I need to get polygon coordinates of building from address. How to?