Convert i18n_process.css to use /deep/ instead of ::shadow and add tests.

chrome/chrome_resources.gyp

 # Copyright (c) 2012 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.
 {
   'variables': {
     'grit_out_dir': '<(SHARED_INTERMEDIATE_DIR)/chrome',
     'about_credits_file': '<(SHARED_INTERMEDIATE_DIR)/about_credits.html',
     'additional_modules_list_file': '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/internal/additional_modules_list.txt',
     'omnibox_mojom_file': '<(SHARED_INTERMEDIATE_DIR)/chrome/browser/ui/webui/omnibox/omnibox.mojom.js',
   },
@@ skipping 581 matching lines @@
           'action_name': 'generate_options_test_resources',
           'variables': {
             'grit_grd_file': 'browser/resources/options_test_resources.grd',
           },
           'includes': [ '../build/grit_action.gypi' ],
         },
       ],
       'includes': [ '../build/grit_target.gypi' ],
     },
     {
+      # GN version: //chrome/test/data/resources:webui_test_resources
+      'target_name': 'webui_test_resources',
+      'type': 'none',
+      'actions': [
+        {
+          'action_name': 'generate_webui_test_resources',
+          'variables': {
+            'grit_grd_file': 'test/data/webui_test_resources.grd',
+          },
+          'includes': [ '../build/grit_action.gypi' ],
+        },
+      ],
+      'includes': [ '../build/grit_target.gypi' ],
+    },
+    {
       # GN version: //chrome:browser_tests_pak
       'target_name': 'browser_tests_pak',
       'type': 'none',
       'dependencies': [
         'options_test_resources',
+        'webui_test_resources',
       ],
       'actions': [
         {
           'action_name': 'repack_browser_tests_pak',
           'variables': {
             'pak_inputs': [
               '<(SHARED_INTERMEDIATE_DIR)/chrome/options_test_resources.pak',
+              '<(SHARED_INTERMEDIATE_DIR)/chrome/webui_test_resources.pak',
             ],
             'pak_output': '<(PRODUCT_DIR)/browser_tests.pak',
           },
           'includes': [ '../build/repack_action.gypi' ],
         },
       ],
     },
     {
       # GN version: //chrome/browser:about_credits
       'target_name': 'about_credits',
@@ skipping 19 matching lines @@
                      '<(generator_path)',
                      'credits',
                      '<(about_credits_file)',
           ],
           'message': 'Generating about:credits',
         },
       ],
     },
   ], # targets
 }