When certain display configuration changes happen, ash first fades the screen to black then does configuration. After configuration is finished the screen fades back in.

This all happens in the browser process in classic ash. In mustash, display configuration will happen in the mus-ws process but the animations will happen in the WM process. We need mus-ws to send an IPC to the WM for the start configuration animation, wait for a response back, try to change the display configuration, then send an IPC to the WM for the end configuration animation.