Improve action bar transition

Improves the transition of the action bar between
the collapsed and expanded states.

Bug: 28935363
Change-Id: I89efe95aa045d04bab4208a001f82cb69b38fce5
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java b/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
index aedc7df..28a6851 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
@@ -193,6 +193,13 @@
         mGroupExpansionChanging = changing;
     }
 
+    @Override
+    public void setActualHeightAnimating(boolean animating) {
+        if (mPrivateLayout != null) {
+            mPrivateLayout.setContentHeightAnimating(animating);
+        }
+    }
+
     public NotificationContentView getPrivateLayout() {
         return mPrivateLayout;
     }