Refactor //ios:all target in preparation of upstreaming.

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")
 
+group("all_tests") {
+  testonly = true
+  deps = [
+    ":ios_web_shell_egtests",
+  ]
+}
+
 ios_eg_test("ios_web_shell_egtests") {
   sources = [
     "context_menu_egtest.mm",
     "meta_tags_egtest.mm",
     "navigation_egtest.mm",
     "page_state_egtest.mm",
     "pdf_egtest.mm",
     "plugin_placeholder_egtest.mm",
     "redirect_egtest.mm",
   ]
@@ skipping 67 matching lines @@
   sources = [
     "http_server_files/basic_navigation_test.html",
     "http_server_files/tall_page.html",
     "http_server_files/testpage.pdf",
   ]
   outputs = [
     "{{bundle_resources_dir}}/{{source_root_relative_dir}}/" +
         "{{source_file_part}}",
   ]
 }