title: Android shouldShowRequestPermissionRationale has a bug?
body: <p>I think there is a bug <code>shouldShowRequestPermissionRationale</code></p>
  
  <p>Code is...</p>
  
  <pre><code>@Override
  protected void onResume() {
      super.onResume();
      if(ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_DENIED &amp;&amp;
              ContextCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_DENIED) {
          if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_COARSE_LOCATION) ||
                  ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) {
              new AlertDialog.Builder(this)....show();
      } else {
          // do something...
  }
  </code></pre>
  
  <p>Installed the app first, We do not allow the permission. So when onResume is called, AlertDialog should appears. But it's not appear...</p>
  
  <p>If we go into the setting of the app, and allow the permission. So We play the app code(<code>// do something</code>). Again, we go into the setting of the app, Deny the permission. And we restart the app, AlertDialog appears.</p>
  
  <p>Why the app runs like this ?</p>