Merge "Use null instead of transparent for Material alert dialog sections" into lmp-dev

    <!-- Dialog styles -->

    <style name="AlertDialog.Material" parent="AlertDialog">

        <item name="fullDark">@color/transparent</item>

        <item name="topDark">@color/transparent</item>

        <item name="centerDark">@color/transparent</item>

        <item name="bottomDark">@color/transparent</item>

        <item name="fullBright">@color/transparent</item>

        <item name="topBright">@color/transparent</item>

        <item name="centerBright">@color/transparent</item>

        <item name="bottomBright">@color/transparent</item>

        <item name="bottomMedium">@color/transparent</item>

        <item name="centerMedium">@color/transparent</item>

        <item name="fullDark">@null</item>

        <item name="topDark">@null</item>

        <item name="centerDark">@null</item>

        <item name="bottomDark">@null</item>

        <item name="fullBright">@null</item>

        <item name="topBright">@null</item>

        <item name="centerBright">@null</item>

        <item name="bottomBright">@null</item>

        <item name="bottomMedium">@null</item>

        <item name="centerMedium">@null</item>

        <item name="layout">@layout/alert_dialog_material</item>

        <item name="listLayout">@layout/select_dialog_material</item>

        <item name="progressLayout">@layout/progress_dialog_material</item>