title: onAccessibilityEvent(AccessibilityEvent event) not intercepting notification
body: <p>In my application I have to catch the new incoming email massage notification and play a video on the screen which describe the event.
  I'm using the <code>onAccessibilityEvent(AccessibilityEvent event)</code> to listen to the generated notification.
  I also use the following code for init my AccessibilityService:</p>
  
  <pre><code>    AccessibilityServiceInfo localAccessibilityServiceInfo = new AccessibilityServiceInfo();
      localAccessibilityServiceInfo.eventTypes = AccessibilityEvent.TYPES_ALL_MASK; // AccessibilityEvent.TYPE_NOTIFICATION_STATE_CHANGED;
      localAccessibilityServiceInfo.notificationTimeout = EVENT_NOTIFICATION_TIMEOUT_MILLIS;
      localAccessibilityServiceInfo.feedbackType = AccessibilityServiceInfo.FEEDBACK_AUDIBLE; // AccessibilityServiceInfo.FEEDBACK_VISUAL;
      localAccessibilityServiceInfo.flags &amp;= AccessibilityServiceInfo.DEFAULT;
      setServiceInfo(localAccessibilityServiceInfo);
  </code></pre>
  
  <p>but event never arrived.
  How it can be solved?
  Thanks,
  Eyal.</p>