[gtk/wip/chergert/fix-maximized-shadows] adwaita: disable shadows when window is maximized or fullscreen

[Christian Hergert <chergert src gnome org>]

commit 461fe36707a346957e4efac56ca504a23bfa2006
Author: Christian Hergert <chergert redhat com>
Date:   Wed Feb 3 16:15:02 2021 -0800

    adwaita: disable shadows when window is maximized or fullscreen
    
    These shadows cause a significant draw performance drop for maximized
    windows. Disabling them increases the chances we can have faster scroll
    performance of text.
    
    There is some risk here for systems where they have a dock and you expect
    the shadow to draw beneath that dock for transparency reasons.

 gtk/theme/Adwaita/_common.scss | 3 +++
 1 file changed, 3 insertions(+)
---
diff --git a/gtk/theme/Adwaita/_common.scss b/gtk/theme/Adwaita/_common.scss
index 5588e4fb40..e7c33f8d19 100644
--- a/gtk/theme/Adwaita/_common.scss
+++ b/gtk/theme/Adwaita/_common.scss
@@ -4100,6 +4100,9 @@ window {
 
       &:backdrop { box-shadow: inset 0 0 0 3px $backdrop_bg_color, inset 0 1px $top_hilight; }
     }
+
+    &.maximized,
+    &.fullscreen { box-shadow: none; }
   }
 
   &.maximized,