cogl_texture_get_components can be used on both X11 and Wayland
backends. Technically, the detection is different: we actually
check the actual RENDER format in the old code, while Cogl simply
assumes that any pixmap with a depth >= 32 is ARGB32. Since Cogl
already seems to be working with its internal checks, it makes
more sense to use Cogl's check rather than keeping our own.
cc0488f1e2
