Create a single default variable for visibility lists

Bug: none
Change-Id: Ic744806971748d973b24b44a99c2a69f90df672b
Reviewed-on: https://chromium-review.googlesource.com/c/devtools/devtools-frontend/+/3021233
Reviewed-by: Tim van der Lippe <[email protected]>
Commit-Queue: Alex Rudenko <[email protected]>
diff --git a/front_end/visibility.gni b/front_end/visibility.gni
new file mode 100644
index 0000000..ec9d580
--- /dev/null
+++ b/front_end/visibility.gni
@@ -0,0 +1,7 @@
+# Copyright 2021 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+declare_args() {
+  devtools_visibility = []
+}