Convert GN visibility variables to lists.

build/secondary/testing/gtest/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.
 
 config("gtest_config") {
   visibility = [
     ":*",
     "//testing/gmock:*",  # gmock also shares this config.
   ]
 
@@ skipping 36 matching lines @@
 
       # GTEST_USE_OWN_TR1_TUPLE only works if GTEST_HAS_TR1_TUPLE is set.
       # gtest r625 made it so that GTEST_HAS_TR1_TUPLE is set to 0
       # automatically on android, so it has to be set explicitly here.
       "GTEST_HAS_TR1_TUPLE=1",
     ]
   }
 }
 
 config("gtest_direct_config") {
-  visibility = ":*"
+  visibility = [ ":*" ]
   defines = [ "UNIT_TEST" ]
 }
 
 static_library("gtest") {
   sources = [
     "include/gtest/gtest-death-test.h",
     "include/gtest/gtest-message.h",
     "include/gtest/gtest-param-test.h",
     "include/gtest/gtest-printers.h",
     "include/gtest/gtest-spi.h",
@@ skipping 39 matching lines @@
   direct_dependent_configs = [ ":gtest_direct_config" ]
 
   configs -= [ "//build/config/compiler:chromium_code" ]
   configs += [ "//build/config/compiler:no_chromium_code" ]
 }
 
 source_set("gtest_main") {
   sources = [ "src/gtest_main.cc" ]
   deps = [ ":gtest" ]
 }