Explicitly initialize secondary renderers for layout tests.

content/shell/BUILD.gn

 # 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.
 
 import("//build/config/features.gni")
 import("//build/config/sanitizers/sanitizers.gni")
 import("//build/config/ui.gni")
 import("//build/config/win/console_app.gni")
 import("//build/config/win/manifest.gni")
 import("//media/media_options.gni")
@@ skipping 66 matching lines @@
     "browser/layout_test/layout_test_notification_manager.cc",
     "browser/layout_test/layout_test_notification_manager.h",
     "browser/layout_test/layout_test_permission_manager.cc",
     "browser/layout_test/layout_test_permission_manager.h",
     "browser/layout_test/layout_test_push_messaging_service.cc",
     "browser/layout_test/layout_test_push_messaging_service.h",
     "browser/layout_test/layout_test_resource_dispatcher_host_delegate.cc",
     "browser/layout_test/layout_test_resource_dispatcher_host_delegate.h",
     "browser/layout_test/layout_test_url_request_context_getter.cc",
     "browser/layout_test/layout_test_url_request_context_getter.h",
-    "browser/layout_test/notify_done_forwarder.cc",
-    "browser/layout_test/notify_done_forwarder.h",
+    "browser/layout_test/secondary_test_window_observer.cc",
+    "browser/layout_test/secondary_test_window_observer.h",
     "browser/layout_test/test_info_extractor.cc",
     "browser/layout_test/test_info_extractor.h",
     "browser/shell.cc",
     "browser/shell.h",
     "browser/shell_access_token_store.cc",
     "browser/shell_access_token_store.h",
     "browser/shell_android.cc",
     "browser/shell_application_mac.h",
     "browser/shell_application_mac.mm",
     "browser/shell_browser_context.cc",
@@ skipping 421 matching lines @@
       ":content_shell_lib",
     ]
   }
 }
 
 mojom("mojo_bindings") {
   sources = [
     "common/layout_test/layout_test_bluetooth_fake_adapter_setter.mojom",
   ]
 }