SysUI: Display group children when no summary is present

Also move common notification filtering into NotificationData
such that clients won't have to do it themselves anymore.

Probably also fixes a couple of multi-user issues.

Bug: 16302692
Bug: 16224431
Change-Id: Ic3c11cd1a224044486f5544e068ca5297d30c521
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
index 6644a6c..cccfb7b 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
@@ -1346,7 +1346,7 @@
         float factor = 1f;
         if (mNotificationStackScroller.getNotGoneChildCount() > 0) {
             factor = 0.6f;
-        } else if (!mStatusBar.hasNotifications()) {
+        } else if (!mStatusBar.hasActiveNotifications()) {
             factor = 0.4f;
         }
         mEmptyDragAmount = amount * factor;