src/vs/platform/backup/electron-main/backupMainService.ts/BackupMainService/hasBackups
class BackupMainService:	private hasBackups(backupLocation: IWorkspaceBackupInfo | IEmptyWindowBackupInfo | URI): Promise<boolean> {
		let backupPath: string;

		// Folder
		if (URI.isUri(backupLocation)) {
			backupPath = this.getBackupPath(this.getFolderHash(backupLocation));
		}

		// Workspace
		else if (isWorkspaceBackupInfo(backupLocation)) {
			backupPath = this.getBackupPath(backupLocation.workspace.id);
		}

		// Empty
		else {
			backupPath = backupLocation.backupFolder;
		}

		return this.doHasBackups(backupPath);
	}