[ios] Implemented Meta Tags EarlGrey tests.

ios/web/shell/test/BUILD.gn

 # 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.
 
 import("//ios/build/config.gni")
 import("//ios/third_party/earl_grey/ios_eg_test.gni")
 
 ios_eg_test("ios_web_shell_test") {
   sources = [
+    "meta_tags_egtest.mm",
     "web_shell_navigation_egtest.mm",
   ]
 
   deps = [
     "//base",
     "//ios/web:test_support",
     "//ios/web/shell",
     "//ios/web/shell/test:earl_grey_test_support",
 
     # All shared libraries must have the sanitizer deps to properly link in
@@ skipping 40 matching lines @@
 bundle_data("bundle") {
   visibility = [ ":ios_web_shell_test_host" ]
   sources = [
     "http_server_files/basic_navigation_test.html",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_root_relative_dir}}/" +
         "{{source_file_part}}",
   ]
 }