Thanks, LGTM!
Note that with this MR we can sometimes get artifacts in GL applications such as: 
However this is not a problem with the change itself, but rather this change is interacting with two existing deficiencies in the driver:
1. `wayland_window_surface_set_clip()` is not implemented, hence we get such artifacts in our committed window surface buffers. 2. OpenGL surfaces not presented opaquely hence we can actually see the artifacts in the window surface behind the GL subsurface. We might want to revisit using EGL_EXT_present_opaque now that https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/28153 has been merged, although this would require a Mesa version check in the Wayland driver to use the feature safely.