If a Crostini app needs to launch the Container before the app can start, we show a spinner on the app icon in the shelf. The current behavior is that the spinner cancels when the app itself launches. We may want to change it so that the spinner cancels when the Container launches. See this comment https://bugs.chromium.org/p/chromium/issues/detail?id=851939#c1

The cancellation of spinners and insertion of normal icons in the shelf is pretty streamlined. Adding this special behavior will be tricky and will raise other problems (like shelf items possibly changing position when the spinner cancels).