src/vs/workbench/api/browser/mainThreadTheming.ts/MainThreadTheming/constructor
class MainThreadTheming:	constructor(
		extHostContext: IExtHostContext,
		@IThemeService themeService: IThemeService
	) {
		this._themeService = themeService;
		this._proxy = extHostContext.getProxy(ExtHostContext.ExtHostTheming);

		this._themeChangeListener = this._themeService.onDidColorThemeChange(e => {
			this._proxy.$onColorThemeChange(this._themeService.getColorTheme().type);
		});
		this._proxy.$onColorThemeChange(this._themeService.getColorTheme().type);
	}