Update iOS GN templates.

build/config/ios/rules.gni

 # Copyright 2015 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.
 
 ios_app_script = "//build/config/ios/ios_app.py"
 
 template("code_sign_ios") {
   assert(defined(invoker.entitlements_path),
          "The path to the entitlements .xcent file")
   assert(defined(invoker.identity), "The code signing identity")
@@ skipping 162 matching lines @@
         ":$plist_gen_target_name",
       ]
     }
   } else {
     # This avoids a potential unused variable warning in the caller.
     entitlements_path = entitlements_path
   }
 
   # Top level group
   group(target_name) {
+    forward_variables_from(invoker, [ "visibility" ])
     deps = [
       ":$bin_gen_target_name",
       ":$plist_gen_target_name",
     ]
     if (invoker.code_signing_identity != "") {
       deps += [ ":$code_sign_gen_target_name" ]
     }
   }
 }