Add initial support for native Linux desktop notifications

chrome/browser/flag_descriptions.h

Index: chrome/browser/flag_descriptions.h
diff --git a/chrome/browser/flag_descriptions.h b/chrome/browser/flag_descriptions.h
index 9e97ec7c9d7d892dd9a82f229e86008569aca074..85b572476c55234d7623140838b61270c4ebd945 100644
--- a/chrome/browser/flag_descriptions.h
+++ b/chrome/browser/flag_descriptions.h
@@ -3132,6 +3132,14 @@ extern const char kEnableEhvInputDescription[];
 
 #endif  // #if defined(OS_CHROMEOS)
 
+#if defined(OS_LINUX) && !defined(OS_CHROMEOS)
+// Name of the about: flag for enabling freedesktop system notifications.
+extern const char kUseSystemNotificationsName[];
+
+// Description of the about: flag enabling freedesktop system notifications.
+extern const char kUseSystemNotificationsDescription[];
+#endif  // defined(USE_GLIB) && defined(USE_GIO)
+
 }  // namespace flag_descriptions
 
 #endif  // CHROME_BROWSER_FLAG_DESCRIPTIONS_H_