Ensure tests have an active task runner

chrome/browser/chromeos/dbus/printer_service_provider_unittest.cc

 // Copyright (c) 2012 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.
 
 #include "chrome/browser/chromeos/dbus/printer_service_provider.h"
 
 #include "base/command_line.h"
 #include "base/strings/stringprintf.h"
 #include "chrome/browser/chromeos/login/users/scoped_user_manager_enabler.h"
 #include "chrome/browser/chromeos/profiles/profile_helper.h"
 #include "chrome/browser/notifications/notification.h"
 #include "chrome/browser/notifications/notification_test_util.h"
 #include "chrome/browser/notifications/notification_ui_manager.h"
 #include "chrome/test/base/testing_profile.h"
 #include "chromeos/chromeos_switches.h"
 #include "chromeos/dbus/services/service_provider_test_helper.h"
 #include "components/user_manager/fake_user_manager.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "dbus/message.h"
 #include "extensions/browser/extension_registry.h"
 #include "extensions/common/extension_builder.h"
 #include "extensions/common/value_builder.h"
 #include "third_party/cros_system_api/dbus/service_constants.h"
 
 namespace chromeos {
 
 const char kPrinterAdded[] = "PrinterAdded";
 
@@ skipping 95 matching lines @@
                  .Set("app",
                       extensions::DictionaryBuilder().Set(
                           "background",
                           extensions::DictionaryBuilder().Set(
                               "scripts",
                               extensions::ListBuilder().Append("bg.js"))))
                  .Set("permissions", *permissions_builder))
         .Build();
   }
 
+  content::TestBrowserThreadBundle thread_bundle_;
   StubNotificationUIManager notification_ui_manager_;
   TestingProfile profile_;
   user_manager::FakeUserManager* user_manager_;
   chromeos::ScopedUserManagerEnabler user_manager_enabler_;
 
   MockPrinterServiceProvider service_provider_;
   ServiceProviderTestHelper test_helper_;
 
  private:
   DISALLOW_COPY_AND_ASSIGN(PrinterServiceProviderAppSearchEnabledTest);
@@ skipping 172 matching lines @@
   ASSERT_TRUE(response.get());
   dbus::MessageReader reader(response.get());
   ASSERT_FALSE(reader.HasMoreData());
   test_helper_.TearDown();
 
   EXPECT_EQ(0u, notification_ui_manager_.GetNotificationCount());
 }
 
 }  // namespace chromeos