The WindowService2(?) of CrOS

Recently, WS was replaced with WS2:

• 1144255 window-service: removes mus_demo, test_wm, and some unnecessary deps

• Issue 865689  Remove window-service

I ran mus_demo to test ozone-gbm, but now it’s gone. :-( So, I need to figure it out what is the difference between WS1 and WS2.

What is the Window Service of ChromeOS? Window Service is a kind of Window Compositor like Weston. It is a separate process from the browser process in CrOS. Some of CrOS features are part of the browser process, but those features will be a separate process using the WindowService.

For more details, see https://cs.chromium.org/chromium/src/services/ws/README.md

“Clients establish a connection to the WindowService by configuring Aura with a mode of MUS. See aura::Env::Mode for details. The WindowService provides a way for one client to embed another client in a specific window (application composition). Embedding establishes a connection to a new client and provides the embedded client with a window to use. See the mojom for more details. For example, on Chrome OS, Ash uses the WindowService to enable separate processes, such as the tap_visualizer, to connect to the WindowService. The tap_visualizer is a client of the WindowService. The tap_visualizer uses the WindowService to create and manage windows, receive events, and ultimately draw to the screen (using Viz). This is mostly seamless to the tap_visualizer. The tap_visualizer configures Views to use Mus, which results in Views and Aura, using the WindowService.”

CrOS is now becoming more like a regular desktop. I’m not sure this is a good decision.