Notification history UI buff

Fixes: 182155974
Test: visual test
Change-Id: I028381407504b3cf390987a6fa11c041fddf6198

src/com/android/settings/notification/history/NotificationSbnViewHolder.java

@@ -75,6 +75,10 @@ public class NotificationSbnViewHolder extends RecyclerView.ViewHolder {
         mIcon.setImageDrawable(icon);
     }
 
+    void setIconBackground(Drawable background) {
+        mIcon.setBackground(background);
+    }
+
     void setPackageLabel(String pkg) {
         mPkgName.setText(pkg);
     }