Fix stale NSSL "fling" state caused by no-op fling

If a fling gesture ends with the current Y position in the exact end
position for the fling, then the code to run the fling animation is
bypassed, but the flag in AmbientState tracking whether a fling is
active is never reset. This CL replaces the short circuit logic with the
standard fling-end logic, ensuring that all expected code paths are
executed.

Fixes: 234824085
Fixes: 237272856
Test: manual
  1. Enter lockscreen
  2. Swipe up and then down to the exact same position, in one
     continuous gesture
  3. Wait for a notification update
  Observe: Shade resizes correctly to match the new contents
Change-Id: Ie8ddf1dbaaf1ba607657646db05d3eb622fc9415
Merged-In: Ie8ddf1dbaaf1ba607657646db05d3eb622fc9415
(cherry picked from commit 7f387f9ae9)

packages/SystemUI/src/com/android/systemui/statusbar/phone/PanelViewController.java

@@ -599,9 +599,7 @@ public abstract class PanelViewController {
             float collapseSpeedUpFactor, boolean expandBecauseOfFalsing) {
         if (target == mExpandedHeight && mOverExpansion == 0.0f) {
             // We're at the target and didn't fling and there's no overshoot
-            endJankMonitoring(CUJ_NOTIFICATION_SHADE_EXPAND_COLLAPSE);
-            mKeyguardStateController.notifyPanelFlingEnd();
-            notifyExpandingFinished();
+            onFlingEnd(false /* cancelled */);
             return;
         }
         mIsFlinging = true;

packages/SystemUI/tests/src/com/android/systemui/statusbar/phone/NotificationPanelViewControllerTest.java

@@ -985,6 +985,21 @@ public class NotificationPanelViewControllerTest extends SysuiTestCase {
         verify(mKeyguardStateController).notifyPanelFlingEnd();
     }
 
+    @Test
+    public void testSwipe_exactlyToTarget_notifiesNssl() {
+        // No over-expansion
+        mNotificationPanelViewController.setOverExpansion(0f);
+        // Fling to a target that is equal to the current position (i.e. a no-op fling).
+        mNotificationPanelViewController.flingToHeight(
+                0f,
+                true,
+                mNotificationPanelViewController.mExpandedHeight,
+                1f,
+                false);
+        // Verify that the NSSL is notified that the panel is *not* flinging.
+        verify(mNotificationStackScrollLayoutController).setPanelFlinging(false);
+    }
+
     @Test
     public void testDoubleTapRequired_Keyguard() {
         FalsingManager.FalsingTapListener listener = getFalsingTapListener();