src/vs/workbench/browser/parts/compositeBar.ts/CompositeBarModel/updateActivity
class CompositeBarModel:	updateActivity(id: string): void {
		const item = this.findItem(id);
		if (item) {
			if (item.activity.length) {
				const [{ badge, clazz }] = item.activity;
				item.activityAction.setBadge(badge, clazz);
			}
			else {
				item.activityAction.setBadge(undefined);
			}
		}
	}