Convert ios_web_shell_test to GN.

ios/web/ios_web_shell_tests.gyp

 # Copyright 2016 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': {
     'chromium_code': 1,
   },
   'targets': [
     {
+      # GN version: //ios/web/shell/test:ios_web_shell_test
       'target_name': 'ios_web_shell_test',
       'type': 'loadable_module',
       'mac_xctest_bundle': 1,
       'variables': {
         'test_host': '<(_target_name)_host',
       },
       'dependencies': [
         '<(test_host)',
       ],
       'xcode_settings': {
@@ skipping 12 matching lines @@
       'link_settings': {
         'libraries': [
           'Foundation.framework',
           'XCTest.framework',
         ],
       },
     },
     {
       # Create a test host for earl grey tests, so Xcode 7.3 and above
       # doesn't contaminate the app structure.
+      # GN version: //ios/web/shell/test:ios_web_shell_test_host
       'target_name': 'ios_web_shell_test_host',
       'includes': [
         'ios_web_shell_exe.gypi',
       ],
       'link_settings': {
         'libraries': [
           'XCTest.framework',
         ],
       },
       'xcode_settings': {
@@ skipping 41 matching lines @@
             'ditto',
             '${BUILT_PRODUCTS_DIR}/EarlGrey.framework',
             '${BUILT_PRODUCTS_DIR}/<(_target_name).app/Frameworks/EarlGrey.framework',
           ],
         },
       ],
     },
     {
       # TODO(crbug.com/606815): Refactor out code that is common across Chrome
       # and the web shell.
+      # GN version: //ios/web/shell/test:earl_grey_test_support
       'target_name': 'ios_web_shell_earl_grey_test_support',
       'type': 'static_library',
       'dependencies': [
         '<(DEPTH)/ios/third_party/earl_grey/earl_grey.gyp:EarlGrey',
         'ios_web.gyp:ios_web_earl_grey_test_support',
         '../testing/earl_grey/earl_grey_support.gyp:earl_grey_support',
       ],
       'sources': [
         'shell/test/app/navigation_test_util.h',
         'shell/test/app/navigation_test_util.mm',
         'shell/test/app/web_shell_test_util.h',
         'shell/test/app/web_shell_test_util.mm',
         'shell/test/app/web_view_interaction_test_util.h',
         'shell/test/app/web_view_interaction_test_util.mm',
         'shell/test/earl_grey/shell_matchers.h',
         'shell/test/earl_grey/shell_matchers.mm',
       ],
     },
   ],
 }