title: Angular 6 pipe does not render material icon
body: <p>When i would like to show a material icon trough an Angular pipe, it does not work.</p>
  
  <p>Imagine the case, when you have some data and you want to convert it to an icon, example:
  You have a list about people who likes ice cream or not, if he likes it, you have the data 'like' and if he does not you have the data 'dislike' and this two parameters you want to convert to an icon 'like' will be '<code>&lt;mat-icon&gt;favorite&lt;/mat-icon&gt;</code>' and 'dislike' will be something else.
  I thought it is going to be easy if i use some Pipe but it does not render the icon :(</p>
  
  <p>Here is the example: <a href="https://stackblitz.com/edit/angular-uasanh" rel="nofollow noreferrer">https://stackblitz.com/edit/angular-uasanh</a></p>
  
  <p>I assume this is happen because of the chain of rendering elements.</p>
  
  <p>Can anyone provide me some instruction how to make it work?</p>