Define gyp targets for mojo/public/* in mojo/public/mojo_public.gyp

mojo/public/cpp/environment/tests/BUILD.gn

 # 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.
 
-# GYP version: mojo/mojo_public_tests.gypi:mojo_public_environment_unittests
+# GYP version: mojo/mojo_base.gyp:mojo_public_environment_unittests
 test("mojo_public_environment_unittests") {
   sources = [
     "async_waiter_unittest.cc",
     "logger_unittest.cc",
     "logging_unittest.cc",
   ]
 
   deps = [
     "//mojo/common/test:run_all_unittests",
     "//mojo/public/c/environment",
     "//mojo/public/cpp/environment:standalone",
     "//mojo/public/cpp/system",
     "//mojo/public/cpp/test_support:test_utils",
     "//mojo/public/cpp/utility",
     "//testing/gtest",
   ]
 }