[Flexiglass] Add a shadow to HUNs over GONE

HUNs used to have a z translation, when they were displayed outside the
shade over launcher. They have lost it over some refactors, which forces
ENR#isAboveShelf() to return false, which causes NSSL's child placement
logic to hit unexpected paths, which can ultimately result in some
flickering while snoozing a Notification.

Bug: 391204020
Test: post a HUN over launcher -> check its shadow
Flag: com.android.systemui.scene_container
Change-Id: I422207e3bf1c6e6614ec17138ec2d4ccab2ef283

3 files changed, 24 insertions, 5 deletions

diff --git a/packages/SystemUI/multivalentTests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt b/packages/SystemUI/multivalentTests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
index 01ba4df3a314..7603eecd27ff 100644
--- a/packages/SystemUI/multivalentTests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
+++ b/packages/SystemUI/multivalentTests/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithmTest.kt
@@ -146,6 +146,20 @@ class StackScrollAlgorithmTest(flags: FlagsParameterization) : SysuiTestCase() {
     }
 
     @Test
+    @EnableSceneContainer
+    fun resetViewStates_defaultHun_hasShadow() {
+        val headsUpTop = 200f
+        ambientState.headsUpTop = headsUpTop
+
+        whenever(notificationRow.isPinned).thenReturn(true)
+        whenever(notificationRow.isHeadsUp).thenReturn(true)
+
+        stackScrollAlgorithm.resetViewStates(ambientState, 0)
+
+        assertThat(notificationRow.viewState.zTranslation).isGreaterThan(baseZ)
+    }
+
+    @Test
     @DisableSceneContainer
     fun resetViewStates_defaultHunWhenShadeIsOpening_yTranslationIsInset() {
         whenever(notificationRow.isPinned).thenReturn(true)
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ExpandableNotificationRow.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ExpandableNotificationRow.java
index 66a0fb4ee4ab..9dd007bf162a 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ExpandableNotificationRow.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/row/ExpandableNotificationRow.java
@@ -4228,6 +4228,7 @@ public class ExpandableNotificationRow extends ActivatableNotificationView
             pw.print(", isPinned: " + isPinned());
             pw.print(", expandedWhenPinned: " + mExpandedWhenPinned);
             pw.print(", isMinimized: " + mIsMinimized);
+            pw.print(", isAboveShelf: " + isAboveShelf());
 
             pw.println();
             if (NotificationContentView.INCLUDE_HEIGHTS_TO_DUMP) {
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
index 06b989aaab57..08692bea2292 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/notification/stack/StackScrollAlgorithm.java
@@ -1227,13 +1227,17 @@ public class StackScrollAlgorithm {
         float baseZ = ambientState.getBaseZHeight();
 
         if (SceneContainerFlag.isEnabled()) {
-            // SceneContainer flags off this logic, and just sets the baseZ because:
+            // SceneContainer simplifies this logic, because:
             // - there are no overlapping HUNs anymore, no need for multiplying their shadows
             // - shadows for HUNs overlapping with the stack are now set from updateHeadsUpStates
-            // - shadows for HUNs overlapping with the shelf are NOT set anymore, because it only
-            // happens on AOD/Pulsing, where they're displayed on a black background so a shadow
-            // wouldn't be visible.
-            childViewState.setZTranslation(baseZ);
+            if (child.isPinned() || ambientState.getTrackedHeadsUpRow() == child) {
+                // set a default elevation on the HUN, which would be overridden
+                // from updateHeadsUpStates if it is displayed in the shade
+                childViewState.setZTranslation(baseZ + mPinnedZTranslationExtra);
+            } else {
+                // set baseZ for every notification
+                childViewState.setZTranslation(baseZ);
+            }
         } else {
             if (child.mustStayOnScreen() && !childViewState.headsUpIsVisible
                     && !ambientState.isDozingAndNotPulsing(child)