Bug 1844346 - Use prefersColorSchemeOverride to inherit dark PBM them…

…e for profile creation wizard dialog. r=desktop-theme-reviewers,dao

This is similar to the fix we did for Bug 1749377 where Page Info windows opened from PBM windows didn't apply the dark theme correctly.

Differential Revision: https://phabricator.services.mozilla.com/D184498

toolkit/profile/content/createProfileWizard.js

@@ -24,6 +24,18 @@ var gProfileDisplay;
 
 // Called once when the wizard is opened.
 function initWizard() {
+  // Inherit color scheme overrides from parent window. This is to inherit the
+  // color scheme of dark themed PBM windows.
+  let openerColorSchemeOverride =
+    window.opener?.browsingContext?.top.prefersColorSchemeOverride;
+  if (
+    openerColorSchemeOverride &&
+    window.browsingContext == window.browsingContext.top
+  ) {
+    window.browsingContext.prefersColorSchemeOverride =
+      openerColorSchemeOverride;
+  }
+
   try {
     gProfileService = C[ToolkitProfileService].getService(
       I.nsIToolkitProfileService