src/vs/workbench/contrib/terminal/browser/terminalIcon.ts/getColorClass
export function getColorClass(terminalOrColorKey: ITerminalInstance | IExtensionTerminalProfile | ITerminalProfile | string): string | undefined {
	let color = undefined;
	if (typeof terminalOrColorKey === 'string') {
		color = terminalOrColorKey;
	} else if (terminalOrColorKey.color) {
		color = terminalOrColorKey.color.replace(/\./g, '_');
	} else if (ThemeIcon.isThemeIcon(terminalOrColorKey.icon) && terminalOrColorKey.icon.color) {
		color = terminalOrColorKey.icon.color.id.replace(/\./g, '_');
	}
	if (color) {
		return `terminal-icon-${color.replace(/\./g, '_')}`;
	}
	return undefined;
}