Add a NotificationTemplateBuilder for Action Center toasts

chrome/test/BUILD.gn

Index: chrome/test/BUILD.gn
diff --git a/chrome/test/BUILD.gn b/chrome/test/BUILD.gn
index 603fa2099d5ee374b138eb0783dd6d15b9b56223..d85f059e8b42d9a0374556b35c95ac49819d1a3c 100644
--- a/chrome/test/BUILD.gn
+++ b/chrome/test/BUILD.gn
@@ -3135,6 +3135,7 @@ test("unit_tests") {
     "../browser/notifications/desktop_notification_profile_util_unittest.cc",
     "../browser/notifications/notification_permission_context_unittest.cc",
     "../browser/notifications/notification_platform_bridge_mac_unittest.mm",
+    "../browser/notifications/notification_template_builder_unittest.cc",  # XXX: Move to the Windows-only section
     "../browser/notifications/platform_notification_service_unittest.cc",
     "../browser/notifications/stub_alert_dispatcher_mac.h",
     "../browser/notifications/stub_alert_dispatcher_mac.mm",