53b040be5c
When dealing with synchronized subsurfaces, we defer buffer attachments until the parent surface state is applied. That causes interaction issues with EGLStream backed buffers, as the client expects the compositor-side stream to be functional after it requests a wl_surface::attach. By allowing the compositor to realize buffers without attaching them, we could resolve the issue above if we define a realized EGLStream buffer as a functional EGLStream (EGLStream + attached consumer). This change moves the texture consumer creation part from the attach function to the realize one. https://bugzilla.gnome.org/show_bug.cgi?id=782575 (cherry picked from commit edd3634bb52a8efc687c612152fda5c996e94d26)