Wait for history backend in popup blocker test

chrome/browser/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/chrome_build.gni")
 import("//build/config/crypto.gni")
 import("//build/config/features.gni")
 import("//build/config/ui.gni")
 import("//build/split_static_library.gni")
 import("//chrome/common/features.gni")
@@ skipping 4118 matching lines @@
     "browsing_data/mock_browsing_data_local_storage_helper.cc",
     "browsing_data/mock_browsing_data_local_storage_helper.h",
     "browsing_data/mock_browsing_data_media_license_helper.cc",
     "browsing_data/mock_browsing_data_media_license_helper.h",
     "browsing_data/mock_browsing_data_quota_helper.cc",
     "browsing_data/mock_browsing_data_quota_helper.h",
     "browsing_data/mock_browsing_data_service_worker_helper.cc",
     "browsing_data/mock_browsing_data_service_worker_helper.h",
     "download/download_test_file_activity_observer.cc",
     "download/download_test_file_activity_observer.h",
+    "history/history_test_utils.cc",
+    "history/history_test_utils.h",
     "media/webrtc/fake_desktop_media_list.cc",
     "media/webrtc/fake_desktop_media_list.h",
     "net/dns_probe_test_util.cc",
     "net/dns_probe_test_util.h",
     "net/url_request_mock_util.cc",
     "net/url_request_mock_util.h",
     "notifications/notification_test_util.cc",
     "notifications/notification_test_util.h",
     "notifications/stub_notification_platform_bridge.cc",
     "notifications/stub_notification_platform_bridge.h",
@@ skipping 251 matching lines @@
   # linking all of the test support.
   static_library("pepper_cdm_test_constants") {
     testonly = true
     visibility = [ "//chrome/*" ]
     sources = [
       "media/pepper_cdm_test_constants.cc",
       "media/pepper_cdm_test_constants.h",
     ]
   }
 }