Steps to Reproduce

1. Create a Polyline with color: Colors.black
2. Look at the app

Expected results:

A black polyline

Actual results:

A red polyline.

The problem is that the functions that convert Flutter colors (ARGB ints) to CSS color is dropping the last byte (instead of the first one), so

Black: 0xFF000000

Gets converted to: #FF0000 instead of #000000.