title: getRunningAppProcesses returns empty list on Android M(5.1.1)
body: <p>I just tested my app and CM, ATM Android Assistant, etc. All of them can not get the running process list but they works fine on pre OS version. So what's going on with  Android M(5.1.1)? please help!</p>
  
  <pre><code>am = (ActivityManager) getContext().getSystemService(Context.ACTIVITY_SERVICE);
  List&lt;RunningAppProcessInfo&gt; list = am.getRunningAppProcesses();
  Log.i(TAG, "LQ::examine list.size()=" + list.size());
  </code></pre>