src/vs/workbench/browser/parts/views/viewsService.ts/ViewsService/getViewContainerProgressIndicator
class ViewsService:	private getViewContainerProgressIndicator(viewContainer: ViewContainer): IProgressIndicator | undefined {
		const viewContainerLocation = this.viewDescriptorService.getViewContainerLocation(viewContainer);
		if (viewContainerLocation === null) {
			return undefined;
		}

		return this.paneCompositeService.getProgressIndicator(viewContainer.id, viewContainerLocation);
	}