title: Using MatToolTip with icons in Angular 5
body: <p>I am able to use <code>MatToolTip</code> along with a button element:</p>
  
  <pre><code>&lt;button mat-mini-fab color="primary" (click)="fn()"&gt;
                  &lt;span matTooltip="myMessage"&gt;
                    &lt;i class="material-icons"&gt;delete&lt;/i&gt;
                  &lt;/span&gt;
                &lt;/button&gt;
  </code></pre>
  
  <p>But on trying to use it with an icon which is within a <code>div</code> or <code>span</code> tag, it doesn't work:</p>
  
  <pre><code>    &lt;div matToolTip="myMessage"&gt;
        &lt;i style="line-height: 0px; font-size: 25px; cursor: pointer; " (click)="fn()" class="material-icons"&gt;delete&lt;/i&gt;
      &lt;/div&gt;
  </code></pre>
  
  <p>What am I doing wrong?</p>