title: Change back button to arrow-down in Navigation Bar
body: <p>I'm using an <code>AppCompatDialogFragment</code> to show a <code>BottomSheetDialog</code>. Clicking the back button on the <code>Navigation Bar</code> closes the <code>BottomSheetDialog</code>.</p>
  
  <p>I want to change the icon on the <code>Navigation Bar</code> from the back button to the 'arrow-down' icon. This is by default done when the keyboard is shown and I want to replicate it for the Bottom Sheet.</p>
  
  <p>To be clear, here what I have:</p>
  
  <p><a href="https://i.stack.imgur.com/62Vkl.png" rel="noreferrer"><img src="https://i.stack.imgur.com/62Vkl.png" alt="Current"></a></p>
  
  <p>And here is what I need:</p>
  
  <p><a href="https://i.stack.imgur.com/jZ8qr.png" rel="noreferrer"><img src="https://i.stack.imgur.com/jZ8qr.png" alt="This is what I want"></a></p>
  
  <p>Note that the back button is an "arrow-down". </p>
  
  <p>The navigation-bar is a system-ui component and I don't see the way to change it's appearance to look like the navigation-bar displayed when the keyboard is visible.</p>