Convert GN visibility to be a list.

tools/gn/variables.cc

Index: tools/gn/variables.cc
diff --git a/tools/gn/variables.cc b/tools/gn/variables.cc
index be758bda6f412d9397f14d74352f5c6fac15acd6..af75aef874eb97891a8ca3e5c10ae88bdc4d7f1e 100644
--- a/tools/gn/variables.cc
+++ b/tools/gn/variables.cc
@@ -823,9 +823,9 @@ const char kVisibility_HelpShort[] =
 const char kVisibility_Help[] =
     "visibility: A list of labels that can depend on a target.\n"
     "\n"
-    "  A label or a list of labels and label patterns that define which\n"
-    "  targets can depend on the current one. These permissions are checked\n"
-    "  via then \"check\" command (see \"gn help check\").\n"
+    "  A list of labels and label patterns that define which targets can\n"
+    "  depend on the current one. These permissions are checked via the\n"
+    "  \"check\" command (see \"gn help check\").\n"
     "\n"
     "  If visibility is not defined, it defaults to public (\"*\").\n"
     "\n"
@@ -848,22 +848,22 @@ const char kVisibility_Help[] =
     "Examples\n"
     "\n"
     "  Only targets in the current buildfile (\"private\", the default):\n"
-    "    visibility = \":*\"\n"
+    "    visibility = [ \":*\" ]\n"
     "\n"
     "  No targets (used for targets that should be leaf nodes):\n"
     "    visibility = []\n"
     "\n"
     "  Any target (\"public\"):\n"
-    "    visibility = \"*\"\n"
+    "    visibility = [ \"*\" ]\n"
     "\n"
     "  All targets in the current directory and any subdirectory:\n"
-    "    visibility = \"./*\"\n"
+    "    visibility = [ \"./*\" ]\n"
     "\n"
     "  Any target in \"//bar/BUILD.gn\":\n"
-    "    visibility = \"//bar:*\"\n"
+    "    visibility = [ \"//bar:*\" ]\n"
     "\n"
     "  Any target in \"//bar/\" or any subdirectory thereof:\n"
-    "    visibility = \"//bar/*\"\n"
+    "    visibility = [ \"//bar/*\"\n ]"
     "\n"
     "  Just these specific targets:\n"
     "    visibility = [ \":mything\", \"//foo:something_else\" ]\n"