Bug 817873 - Fix scrolling event. r=blassey

mobile/android/base/GeckoAccessibility.java

@@ -166,6 +166,7 @@ public class GeckoAccessibility {
                             view.performAccessibilityAction(AccessibilityNodeInfo.ACTION_ACCESSIBILITY_FOCUS, null);
                             break;
                         case AccessibilityEvent.TYPE_ANNOUNCEMENT:
+                        case AccessibilityEvent.TYPE_VIEW_SCROLLED:
                             final AccessibilityEvent accEvent = AccessibilityEvent.obtain(eventType);
                             view.onInitializeAccessibilityEvent(accEvent);
                             populateEventFromJSON(accEvent, message);