Remove unused target_visibility assignment from mojom gni

mojo/public/tools/bindings/mojom.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.
 
 import("../../mojo_sdk.gni")
 
 # Generate C++/JavaScript/Java/Python/Dart/Go source files from mojom files. The
 # output files will go under the generated file directory tree with the same
 # path as each input file.
 #
@@ skipping 145 matching lines @@
 
   rebased_mojo_sdk_deps = []
   if (defined(invoker.mojo_sdk_deps)) {
     foreach(sdk_dep, invoker.mojo_sdk_deps) {
       # Check that the SDK dep was not mistakenly given as an absolute path.
       assert(get_path_info(sdk_dep, "abspath") != sdk_dep)
       rebased_mojo_sdk_deps += [ rebase_path(sdk_dep, ".", mojo_root) ]
     }
   }
 
-  if (defined(invoker.visibility)) {
-    # Need to save this because the the target_name is overwritten inside the
-    # action to be that of the action itself. Only define this in the case the
-    # var is used to avoid unused var error.
-    target_visibility = [ ":$target_name" ]
-  }
-
   if (defined(invoker.sources)) {
     generator_target_name = target_name + "__generator"
     action_foreach(generator_target_name) {
       script = generator_script
       inputs = generator_sources
       sources = invoker.sources
       outputs = generator_cpp_outputs + generator_dart_outputs +
                 generator_go_outputs + generator_java_outputs +
                 generator_js_outputs + generator_python_outputs
       args = [
@@ skipping 231 matching lines @@
         # //mojo/something:something and we can append "_java" to get the java
         # dependency name.
         full_name = get_label_info(d, "label_no_toolchain")
         deps += [ "${full_name}_java" ]
       }
 
       srcjar_deps = [ ":$java_srcjar_target_name" ]
     }
   }
 }