--- a/layout/style/nsMediaFeatures.cpp
+++ b/layout/style/nsMediaFeatures.cpp
@@ -790,16 +790,52 @@ nsMediaFeatures::features[] = {
     &nsGkAtoms::_moz_swipe_animation_enabled,
     nsMediaFeature::eMinMaxNotAllowed,
     nsMediaFeature::eBoolInteger,
     nsMediaFeature::eUserAgentAndChromeOnly,
     { &nsGkAtoms::swipe_animation_enabled },
     GetSystemMetric
   },
 
+  {
+    &nsGkAtoms::_moz_gtk_csd_available,
+    nsMediaFeature::eMinMaxNotAllowed,
+    nsMediaFeature::eBoolInteger,
+    nsMediaFeature::eUserAgentAndChromeOnly,
+    { &nsGkAtoms::gtk_csd_available },
+    GetSystemMetric
+  },
+
+  {
+    &nsGkAtoms::_moz_gtk_csd_minimize_button,
+    nsMediaFeature::eMinMaxNotAllowed,
+    nsMediaFeature::eBoolInteger,
+    nsMediaFeature::eUserAgentAndChromeOnly,
+    { &nsGkAtoms::gtk_csd_minimize_button },
+    GetSystemMetric
+  },
+
+  {
+    &nsGkAtoms::_moz_gtk_csd_maximize_button,
+    nsMediaFeature::eMinMaxNotAllowed,
+    nsMediaFeature::eBoolInteger,
+    nsMediaFeature::eUserAgentAndChromeOnly,
+    { &nsGkAtoms::gtk_csd_maximize_button },
+    GetSystemMetric
+  },
+
+  {
+    &nsGkAtoms::_moz_gtk_csd_close_button,
+    nsMediaFeature::eMinMaxNotAllowed,
+    nsMediaFeature::eBoolInteger,
+    nsMediaFeature::eUserAgentAndChromeOnly,
+    { &nsGkAtoms::gtk_csd_close_button },
+    GetSystemMetric
+  },
+
   // Internal -moz-is-glyph media feature: applies only inside SVG glyphs.
   // Internal because it is really only useful in the user agent anyway
   //  and therefore not worth standardizing.
   {
     &nsGkAtoms::_moz_is_glyph,
     nsMediaFeature::eMinMaxNotAllowed,
     nsMediaFeature::eBoolInteger,
     nsMediaFeature::eUserAgentAndChromeOnly,