title: Android toolbar setNavigationIcon not working
body: <p>So, I have a BaseActivity in which I have a toolbar and I call setSupportActionBar(toolbar).</p>
  
  <p>In some of my activities that extends BaseActivity, I would like to change the navigation icon (the default arrow) to another drawable. But when I call toolbar.setNavigationIcon(myDrawable) it doesn't work, it still shows the default left pointing arrow icon.</p>
  
  <p>Any idea? 
  Thanks.</p>