title: Screen pinning fails after device restart
body: <p>In my owner device app on Android 6.0 device, I have called <code>setLockTaskPackages()</code> and then <code>startLockTask()</code> like following:</p>
  
  <pre><code>...
  mDPM.setLockTaskPackages("com.foo.myapp");
  ...
  startLockTask(); 
  </code></pre>
  
  <p>It works on screen pinning at the installation of the app, but after device restarts and app start again, screen pinning fails by "screen unpinned" toast.</p>
  
  <p>Thank you in advance for any advice.</p>