title: MatCheckbox preventDefault() and event.checked value
body: <p>How can I achieve a Material checkbox so It won't get checked/unchecked by default (eg. calling <code>preventDefault()</code> on the event) and also get the <code>checked</code> value from the event?</p>
  
  <p>It seems like I can only achieve one of the conditions. Using the <code>(click)</code> event I cannot get the checkbox's value and using the <code>(change)</code> event I can't prevent the default checkbox value change (I will only change the checkbox value if the underlying HTTP request was successful).</p>
  
  <p>Stackblitz: <a href="https://stackblitz.com/edit/matcheckbox-checked" rel="nofollow noreferrer">https://stackblitz.com/edit/matcheckbox-checked</a></p>
  
  <pre><code>&lt;mat-checkbox 
    [checked]="checked"   
    (click)="onClick($event)"
  &gt;onClick me!&lt;/mat-checkbox&gt;
  
  &lt;br/&gt;
  
  &lt;mat-checkbox 
    [checked]="checked"
    (change)="onChange($event); false"
  &gt;onChange me!&lt;/mat-checkbox&gt;
  
  export class CheckboxOverviewExample {
    checked: boolean = false;
  
    onClick(event) {
      event.preventDefault();
      console.log('onClick event.checked ' + event.checked);
      console.log('onClick event.target.checked '+event.target.checked);
    }
  
    onChange(event) {
      // can't event.preventDefault();
      console.log('onChange event.checked '+event.checked);
    }
  }
  </code></pre>
  
  <p>The <code>(click)</code> event prints <code>undefined</code> values, but successfully prevents the event propagation, the <code>(change)</code> event prints the value but will propagate the event.</p>
  
  <p>Connected issues: </p>
  
  <ul>
  <li><a href="https://github.com/angular/material2/issues/1142" rel="nofollow noreferrer">https://github.com/angular/material2/issues/1142</a></li>
  <li><a href="https://github.com/angular/angular/issues/2042" rel="nofollow noreferrer">https://github.com/angular/angular/issues/2042</a></li>
  <li><a href="https://github.com/angular/material2/issues/13156" rel="nofollow noreferrer">https://github.com/angular/material2/issues/13156</a></li>
  </ul>