title: Android Auto Audio Playback - buttons not seen
body: <p>I am writing an app that supports audio playback on Android Auto, by extending <code>MediaBrowserService</code>, as described in the <a href="https://developer.android.com/training/auto/audio/index.html" rel="nofollow">documentation</a>. My code works perfectly fine in the Android Auto Media simulator, but in an actual car, the playback control buttons are not seen. I am still able to play an audio file by selecting it from the list of files; but I can't pause/play or go to next/previous etc. </p>
  
  <p>Anyone else has seen this problem? Any suggestions?</p>