GN rules for everything in //mojo

mojo/mojo_public_tests.gypi

 # 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.
 
 {
   'targets': [
     {
       # GN version: //mojo/public/c/test_support
       'target_name': 'mojo_test_support',
       'type': 'shared_library',
@@ skipping 151 matching lines @@
         # See crbug.com/342893:
         ['OS=="win"', {
           'sources!': [
             'public/cpp/utility/tests/mutex_unittest.cc',
             'public/cpp/utility/tests/thread_unittest.cc',
           ],
         }],
       ],
     },
     {
+      # GN version: //mojo/public/c/system/tests:perftests
       'target_name': 'mojo_public_system_perftests',
       'type': 'executable',
       'dependencies': [
         '../base/base.gyp:base',
         '../testing/gtest.gyp:gtest',
         'mojo_public_test_utils',
         'mojo_run_all_perftests',
         'mojo_utility',
       ],
       'sources': [
@@ skipping 34 matching lines @@
         'mojo_js_bindings_lib',
         'mojo_public_test_interfaces',
         'mojo_run_all_unittests',
       ],
       'sources': [
         'public/js/bindings/tests/run_js_tests.cc',
       ],
     },
   ],
 }