From 07e5ea696665076436ce45db6dfffabe8c767666 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Emilio=20Cobos=20=C3=81lvarez?= <emilio@crisal.io>
Date: Sat, 27 May 2023 16:23:42 +0200
Subject: [PATCH] style: Expose titlebar radius as a chrome-only CSS
 environment variable

Mostly plumbing.

Differential Revision: https://phabricator.services.mozilla.com/D128680
---
 components/style/custom_properties.rs   | 7 ++++++-
 components/style/gecko/media_queries.rs | 7 +++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/components/style/custom_properties.rs b/components/style/custom_properties.rs
index a6908bb4cfa..7e8a1e37f7f 100644
--- a/components/style/custom_properties.rs
+++ b/components/style/custom_properties.rs
@@ -71,7 +71,12 @@ static ENVIRONMENT_VARIABLES: [EnvironmentVariable; 4] = [
     make_variable!(atom!("safe-area-inset-right"), get_safearea_inset_right),
 ];
 
-static CHROME_ENVIRONMENT_VARIABLES: [EnvironmentVariable; 0] = [
+fn get_titlebar_radius(device: &Device) -> VariableValue {
+    VariableValue::pixel(device.titlebar_radius())
+}
+
+static CHROME_ENVIRONMENT_VARIABLES: [EnvironmentVariable; 1] = [
+    make_variable!(atom!("-moz-gtk-csd-titlebar-radius"), get_titlebar_radius),
 ];
 
 impl CssEnvironment {
diff --git a/components/style/gecko/media_queries.rs b/components/style/gecko/media_queries.rs
index 2966363a8eb..a560211d2f3 100644
--- a/components/style/gecko/media_queries.rs
+++ b/components/style/gecko/media_queries.rs
@@ -440,6 +440,13 @@ impl Device {
         }
     }
 
+    /// Returns the gtk titlebar radius in CSS pixels.
+    pub fn titlebar_radius(&self) -> f32 {
+        unsafe {
+            bindings::Gecko_GetLookAndFeelFloat(bindings::LookAndFeel_FloatID::TitlebarRadius as i32)
+        }
+    }
+
     /// Return whether the document is a chrome document.
     #[inline]
     pub fn is_chrome_document(&self) -> bool {