WordPress/src/main/res/drawable/stats_visitors_and_views_legend_background_secondary.xml

<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android" >

    <item>
        <shape android:shape="rectangle">
            <solid android:color="@color/stats_bar_graph_secondary_series"/>
            <corners android:radius="@dimen/stats_button_corner_radius"/>
            <size
                android:width="@dimen/stats_barchart_legend_item"
                android:height="@dimen/stats_barchart_legend_item"/>
        </shape>
    </item>

</layer-list>