Add initial support for native Linux desktop notifications

chrome/common/features.gni

Index: chrome/common/features.gni
diff --git a/chrome/common/features.gni b/chrome/common/features.gni
index 7344feb8d163e70c42f9447af49d37418d3b5fb8..360f8354efc9e0f7b00260f01e801675d056ee47 100644
--- a/chrome/common/features.gni
+++ b/chrome/common/features.gni
@@ -42,6 +42,10 @@ declare_args() {
   # ChromeOS builds have this enabled by default.
   enable_hotwording = is_chrome_branded && is_chromeos
 
+  # Enables usage of the system-provided notification center.
+  enable_native_notifications =
+      is_android || is_mac || (is_desktop_linux && use_glib && use_gio)
+
   enable_one_click_signin =
       is_win || is_mac || (is_linux && !is_chromeos && !is_chromecast)