AOD: show AOD1 instead of AOD2 on double tap

Bug: 30876804
Test: Have a notification showing, turn off screen, double-tap to Ambient Display, observe that device shows only the time and notification icon, not the expanded notification
Change-Id: Ic9b9fc392b67b0411588c1287cdf61ca2397990d

packages/SystemUI/src/com/android/systemui/statusbar/notification/VisualStabilityManager.java

@@ -72,6 +72,9 @@ public class VisualStabilityManager implements OnHeadsUpChangedListener {
      * @param pulsing whether we are currently pulsing for ambient display.
      */
     public void setPulsing(boolean pulsing) {
+        if (mPulsing == pulsing) {
+            return;
+        }
         mPulsing = pulsing;
         updateReorderingAllowed();
     }

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

@@ -5005,8 +5005,12 @@ public class StatusBar extends SystemUI implements DemoMode,
                 @Override
                 public void onPulseStarted() {
                     callback.onPulseStarted();
-                    mStackScroller.setPulsing(true);
-                    mVisualStabilityManager.setPulsing(true);
+                    if (!mHeadsUpManager.getAllEntries().isEmpty()) {
+                        // Only pulse the stack scroller if there's actually something to show.
+                        // Otherwise just show the always-on screen.
+                        mStackScroller.setPulsing(true);
+                        mVisualStabilityManager.setPulsing(true);
+                    }
                 }
 
                 @Override

packages/SystemUI/src/com/android/systemui/statusbar/stack/NotificationStackScrollLayout.java

@@ -4026,6 +4026,9 @@ public class NotificationStackScrollLayout extends ViewGroup
     }
 
     public void setPulsing(boolean pulsing) {
+        if (mPulsing == pulsing) {
+            return;
+        }
         mPulsing = pulsing;
         updateNotificationAnimationStates();
         updateContentHeight();