packages/SystemUI/res/layout/status_bar_notification_row.xml

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="65sp"
    android:orientation="vertical"
    >

    <com.android.systemui.statusbar.LatestItemView android:id="@+id/content"
            android:layout_width="match_parent"
            android:layout_height="64sp"
            android:background="@android:drawable/status_bar_item_background"
            android:focusable="true"
            android:clickable="true"
            android:paddingRight="6sp"
            >
    </com.android.systemui.statusbar.LatestItemView>

    <View
        android:layout_width="match_parent"
        android:layout_height="1sp"
        android:background="@android:drawable/divider_horizontal_bright"
        />

</LinearLayout>