Comment 48 for bug 111061

Yeah, they use colors differently, but you still need up-to-date information from the GTK theme itself to know which colors it's currently using. A static list of colors won't work, since the theme can be changed by the user.

Since each theme engine can use the GTK colors however it wants, you need a separate set of mappings for each engine, so you know which colors it's using for elements that are *similar* to the elements in the Windows theme.