Modified the way icons merge into the shelf

The icon can now also move into the shelf in an animated
way instead of just moving out of it.

Change-Id: Iba4ebd3cd48b5299b89bd0cb2b05bd318e352173
Fixes: 33463805
Test: add notification observe behavior when scrolling
diff --git a/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java b/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
index d1c0073..8ae84cf 100644
--- a/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
+++ b/packages/SystemUI/src/com/android/systemui/statusbar/ExpandableNotificationRow.java
@@ -929,6 +929,10 @@
         return topPadding;
     }
 
+    public float getContentTranslation() {
+        return mPrivateLayout.getTranslationY();
+    }
+
     public interface ExpansionLogger {
         public void logNotificationExpansion(String key, boolean userAction, boolean expanded);
     }