GN + Android: allow to set visibility on android_library targets.

build/config/android/internal_rules.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("//build/config/android/config.gni")
 
 assert(is_android)
 
 
 rebased_android_sdk = rebase_path(android_sdk, root_build_dir)
@@ skipping 796 matching lines @@
     }
 
     _final_deps += [ ":${_template_name}__dex" ]
     dex("${_template_name}__dex") {
       sources = [_jar_path]
       output = _dex_path
     }
   }
 
   group(target_name) {
+    if (defined(invoker.visibility)) {
+      visibility = invoker.visibility
+    }
     deps = _final_deps
     datadeps = _final_datadeps
   }
 }
 
 
 # Runs process_resources.py
 template("process_resources") {
   if (defined(invoker.testonly)) { testonly = invoker.testonly }
 
@@ skipping 111 matching lines @@
 
     if (defined(invoker.clear_dir) && invoker.clear_dir) {
       args += ["--clear"]
     }
 
     if (defined(invoker.args)) {
       args += invoker.args
     }
   }
 }