tdf#156040 pick a better "LightColor" for windows dark theme

in the absence of a better idea, do like StyleSettings::Set3DColors does

Change-Id: I9868d4eb94fb221fcbf5e3a4e4761fb2bd8888fc
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/157681
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolan.mcnamara@collabora.com>
diff --git a/vcl/win/window/salframe.cxx b/vcl/win/window/salframe.cxx
index 7ebe680..7c26ea1 100644
--- a/vcl/win/window/salframe.cxx
+++ b/vcl/win/window/salframe.cxx
@@ -2706,6 +2706,13 @@ void WinSalFrame::UpdateSettings( AllSettings& rSettings )
        GetThemeColor(hTheme, 0, 0, TMT_FILLCOLOR, &color);
        aStyleSettings.SetFaceColor( ImplWinColorToSal( color ) );
        aStyleSettings.SetWindowColor( ImplWinColorToSal( color ) );

        // tdf#156040 in the absence of a better idea, do like
        // StyleSettings::Set3DColors does
        Color aLightColor(ImplWinColorToSal(color));
        aLightColor.DecreaseLuminance(64);
        aStyleSettings.SetLightColor(aLightColor);

        GetThemeColor(hTheme, 0, 0, TMT_TEXTCOLOR, &color);
        aStyleSettings.SetWindowTextColor( ImplWinColorToSal( color ) );
        aStyleSettings.SetToolTextColor( ImplWinColorToSal( color ) );
@@ -2757,6 +2764,7 @@ void WinSalFrame::UpdateSettings( AllSettings& rSettings )
        aStyleSettings.SetWindowColor( ImplWinColorToSal( GetSysColor( COLOR_WINDOW ) ) );
        aStyleSettings.SetWindowTextColor( ImplWinColorToSal( GetSysColor( COLOR_WINDOWTEXT ) ) );
        aStyleSettings.SetToolTextColor( ImplWinColorToSal( GetSysColor( COLOR_WINDOWTEXT ) ) );
        aStyleSettings.SetLightColor( ImplWinColorToSal( GetSysColor( COLOR_3DHILIGHT ) ) );
        aStyleSettings.SetShadowColor( ImplWinColorToSal( GetSysColor( COLOR_3DSHADOW ) ) );
        aStyleSettings.SetDarkShadowColor( ImplWinColorToSal( GetSysColor( COLOR_3DDKSHADOW ) ) );
        aControlTextColor = ImplWinColorToSal(GetSysColor(COLOR_BTNTEXT));
@@ -2781,7 +2789,6 @@ void WinSalFrame::UpdateSettings( AllSettings& rSettings )
    aStyleSettings.SetMenuBarTextColor( aMenuBarTextColor );
    aStyleSettings.SetMenuBarRolloverTextColor( aMenuBarRolloverTextColor );

    aStyleSettings.SetLightColor( ImplWinColorToSal( GetSysColor( COLOR_3DHILIGHT ) ) );
    aStyleSettings.SetLightBorderColor( ImplWinColorToSal( GetSysColor( COLOR_3DLIGHT ) ) );
    aStyleSettings.SetHelpColor( ImplWinColorToSal( GetSysColor( COLOR_INFOBK ) ) );
    aStyleSettings.SetHelpTextColor( ImplWinColorToSal( GetSysColor( COLOR_INFOTEXT ) ) );