Convert GN visibility variables to lists.

third_party/yasm/yasm_assemble.gni

 # 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.
 
 # This provides the yasm_assemble() template which uses YASM to assemble
 # assembly files.
 #
 # Files to be assembled with YASM should have an extension of .asm.
 #
 # Parameters
@@ skipping 92 matching lines @@
   assert(defined(invoker.sources), "Need sources defined for $target_name")
 
   # Only depend on YASM on x86 systems. Force compilation of .asm files for
   # ARM to fail.
   assert(cpu_arch == "x86" || cpu_arch == "x64")
 
   action_name = "${target_name}_action"
   source_set_name = target_name
 
   action_foreach(action_name) {
-    visibility = ":$source_set_name"  # Only the source set can depend on this.
+    # Only the source set can depend on this.
+    visibility = [ ":$source_set_name" ]
 
     script = "//third_party/yasm/run_yasm.py"
     sources = invoker.sources
 
     if (defined(invoker.inputs)) {
       inputs = invoker.inputs
     }
 
     # Executable (first in the args). The binary might be in the root build dir
     # (no cross-compiling) or in a toolchain-specific subdirectory of that
@@ skipping 54 matching lines @@
   source_set(source_set_name) {
     if (defined(invoker.visibility)) {
       visibility = invoker.visibility
     }
 
     sources = get_target_outputs(":$action_name")
 
     deps = [ ":$action_name" ]
   }
 }