sysui: refactor for extensibility.

Bug: 28942127
Change-Id: I2f61127a3c4843c22e15a4c6de1d78f165023b27
(cherry picked from commit fbc83b9837e383513eeae90d35fbc50eebeb06b3)
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 d7bb569..263df45 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/phone/NotificationPanelView.java
@@ -1300,7 +1300,7 @@
         flingSettings(vel, expand, null, false /* isClick */);
     }
 
-    private void flingSettings(float vel, boolean expand, final Runnable onFinishRunnable,
+    protected void flingSettings(float vel, boolean expand, final Runnable onFinishRunnable,
             boolean isClick) {
         float target = expand ? mQsMaxExpansionHeight : mQsMinExpansionHeight;
         if (target == mQsExpansionHeight) {