Conver mojo visibility to be a list.

mojo/views/BUILD.gn

 # Copyright 2014 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.
 
 import("//build/config/ui.gni")
 
 assert(use_aura)
 
 # GYP version: mojo/mojo.gyp:mojo_views_support
 source_set("views") {
@@ skipping 17 matching lines @@
     "//ui/views",
     "//ui/wm",
     "//mojo/aura",
   ]
 }
 
 # GYP version: mojo/mojo.gyp:mojo_views_support_internal
 component("views_internal") {
   output_name = "mojo_views_support_internal"
 
-  visibility = ":views"
+  visibility = [ ":views" ]
 
   sources = [
     "mojo_views_export.h",
     "views_init_internal.cc",
     "views_init_internal.h",
   ]
 
   defines = [ "MOJO_VIEWS_IMPLEMENTATION" ]
 
   deps = [
     "//base",
     "//base:i18n",
     "//base:base_static",
     "//base/third_party/dynamic_annotations",
     "//skia",
     "//third_party/icu",
     "//ui/base",
     "//ui/gfx",
   ]
 }