Comment 1 for bug 1033935

Difficulty: Very Difficult, would not recommend this cycle
Method:
1) Make the decor plugin an interface plugin (like scale, cube, etc)
2) Make DecorWindow::glDecorate a wrappable function
3) Overload it unity side
4) On UnityWindow::glDecorate, draw the decoration texture using GLWindow::glDrawTexture but the "region" should be the size of the scale slot instead of the actual window size (this will probably make it draw at full size, not sure).
Test: Not sure at this point. This may require a bit of 2D matrix manipulation and that will definitely need testing.