Convert GN visibility variables to lists.

google_apis/gcm/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("//third_party/protobuf/proto_library.gni")
 
 component("gcm") {
   sources = [
     "base/mcs_message.cc",
     "base/mcs_message.h",
@@ skipping 40 matching lines @@
     "//base/third_party/dynamic_annotations",
     "//net",
     "//third_party/leveldatabase",
     "//url",
   ]
 
   forward_dependent_configs_from = [ ":proto" ]
 }
 
 proto_library("proto") {
-  visibility = ":*"
+  visibility = [ ":*" ]
   sources = [
     "protocol/android_checkin.proto",
     "protocol/checkin.proto",
     "protocol/mcs.proto",
   ]
 }
 
 static_library("test_support") {
   sources = [
     "base/fake_encryptor.cc",
@@ skipping 51 matching lines @@
   deps = [
     ":proto",
     ":test_support",
     "//base",
     "//base/test:run_all_unittests",
     "//net",
     "//net:test_support",
     "//testing/gtest",
   ]
 }