src/vs/workbench/contrib/debug/browser/debugTitle.ts/DebugTitleContribution/constructor
class DebugTitleContribution:	constructor(
		@IDebugService readonly debugService: IDebugService,
		@IHostService readonly hostService: IHostService,
		@ITitleService readonly titleService: ITitleService
	) {
		const updateTitle = () => {
			if (debugService.state === State.Stopped && !hostService.hasFocus) {
				titleService.updateProperties({ prefix: '🔴' });
			} else {
				titleService.updateProperties({ prefix: '' });
			}
		};
		this.toDispose.push(debugService.onDidChangeState(updateTitle));
		this.toDispose.push(hostService.onDidChangeFocus(updateTitle));
	}