src/vs/workbench/browser/parts/activitybar/activitybarPart.ts/ActivitybarPart/updateActivity
class ActivitybarPart:	private updateActivity(viewContainer: ViewContainer, viewContainerModel: IViewContainerModel): void {
		const activity: IActivity = this.toActivity(viewContainerModel);
		const { activityAction, pinnedAction } = this.getCompositeActions(viewContainer.id);
		activityAction.updateActivity(activity);

		if (pinnedAction instanceof PlaceHolderToggleCompositePinnedAction) {
			pinnedAction.setActivity(activity);
		}

		this.saveCachedViewContainers();
	}