Makes secondary more actionlike by adding a ripple effect

Bug: 16353924
Change-Id: Ic6ffadceb080d83fe9750ae7d152ee539ed0ef99
diff --git a/res/layout/expanding_entry_card_item.xml b/res/layout/expanding_entry_card_item.xml
index 174ddf9..16571a7 100644
--- a/res/layout/expanding_entry_card_item.xml
+++ b/res/layout/expanding_entry_card_item.xml
@@ -88,6 +88,7 @@
         android:layout_alignParentEnd="true"
         android:layout_alignParentTop="true"
         android:visibility="gone"
+        android:background="?android:attr/selectableItemBackgroundBorderless"
         android:layout_marginEnd="@dimen/expanding_entry_card_item_alternate_icon_margin_end"
         android:layout_marginTop="@dimen/expanding_entry_card_item_icon_margin_top"
         android:layout_marginBottom="@dimen/expanding_entry_card_item_alternate_icon_margin_bottom" />