dix: Skip more code in SetRootClip for ROOT_CLIP_INPUT_ONLY
Despite e957a2e5 ("dix: Add hybrid full-size/empty-clip mode to SetRootClip"), I was still seeing all X11 client windows flashing when the root window size changes with rootless Xwayland (e.g. due to hotplugging a monitor).
Skipping this code for ROOT_CLIP_INPUT_ONLY fixes the issue for me.
/cc @daniels
Maybe this is just a gross hack?