Bug 1702879 - Add LookAndFeel::ColorSchemeForDocument so that it can be called from nsNativeThemeCocoa. r=emilio

Depends on D110764

Differential Revision: https://phabricator.services.mozilla.com/D110765

widget/LookAndFeel.h

@@ -430,6 +430,8 @@ class LookAndFeel {
                                               : ColorScheme::Light;
   }
 
+  static ColorScheme ColorSchemeForDocument(const dom::Document& aDoc);
+
   // Whether standins for native colors should be used (that is, colors faked,
   // taken from win7, mostly). This forces light appearance, effectively.
   enum class UseStandins : bool { No, Yes };

widget/nsXPLookAndFeel.cpp

@@ -913,7 +913,7 @@ static bool ShouldUseStandinsForNativeColorForNonNativeTheme(
   return false;
 }
 
-static LookAndFeel::ColorScheme ColorSchemeForDocument(
+LookAndFeel::ColorScheme LookAndFeel::ColorSchemeForDocument(
     const dom::Document& aDoc) {
 #ifdef XP_MACOSX
   if (nsContentUtils::IsChromeDoc(&aDoc) &&