title: ReactJS material-ui use the class `Mui-disabled` for read-only components
body: <p>I'm building a new component from <code>TextField</code> and I need to apply the same style for text fields with the <code>readOnly</code> than <code>disabled</code> property.</p>
  
  <p>So, I was trying to use the property <code>className</code> but it does not work.</p>
  
  <pre><code>// some logic here ..
  
  &lt;TextField
      {...props}
      className={readOnly ? 'Mui-disabled' : undefined}
   /&gt;
  </code></pre>
  
  <p>So, I also tried to use the <code>classses</code> prop, but I don't know how to get the current config from the disabled class.</p>