Merge "Set letterbox background color to system_neutral2_900." into sc-v2-dev

            but isn't supported on the device or both dark scrim alpha and blur radius aren't

            provided.

     -->

    <color name="config_letterboxBackgroundColor">@android:color/system_neutral2_500</color>

    <color name="config_letterboxBackgroundColor">@android:color/system_neutral2_900</color>

    <!-- Horizonal position of a center of the letterboxed app window.

        0 corresponds to the left side of the screen and 1 to the right side. If given value < 0