title: Toolbar title not in center when Back Button is enable
body: <p>I'm trying to display my toolbar title in the center and to do it I use the method which is given in this answer :-<a href="https://stackoverflow.com/a/26548766/4169014">Toolbar Center title</a></p>
  
  <p>However, when I enable back button in my <code>activity</code> by following code: </p>
  
  <pre><code>toolbar = (Toolbar) findViewById(R.id.toolbar);
  setSupportActionBar(toolbar);
  mActionBar = getSupportActionBar();
  mActionBar.setDisplayHomeAsUpEnabled(true);
  mActionBar.setDisplayShowHomeEnabled(true);
  </code></pre>
  
  <p>The title of toolbar doesn't show up in the center but slightly off-centered towards the right.</p>
  
  <p>How can I achieve centered title <strong>without</strong> being <strong>affected by the back button or menu bar?</strong></p>