headHtml method
Snippet JS de inicialização (sem a tag <script>).
Implementation
@override
String headHtml() =>
"!function(f,b,e,v,n,t,s){if(f.fbq)return;n=f.fbq=function(){n.callMethod?n.callMethod.apply(n,arguments):n.queue.push(arguments)};if(!f._fbq)f._fbq=n;n.push=n;n.loaded=!0;n.version='2.0';n.queue=[];t=b.createElement(e);t.async=!0;t.src=v;s=b.getElementsByTagName(e)[0];s.parentNode.insertBefore(t,s)}(window,document,'script','https://connect.facebook.net/en_US/fbevents.js');fbq('init','$pixelId');fbq('track','PageView');";