Ensure tests have an active task runner

chrome/browser/extensions/api/signed_in_devices/signed_in_devices_manager_unittest.cc

 // Copyright 2013 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 "base/memory/scoped_ptr.h"
 #include "base/prefs/pref_service.h"
 #include "base/prefs/testing_pref_store.h"
 #include "chrome/browser/extensions/api/signed_in_devices/signed_in_devices_manager.h"
 #include "chrome/browser/signin/signin_manager_factory.h"
 #include "chrome/browser/sync/profile_sync_service_factory.h"
 #include "chrome/common/extensions/api/signed_in_devices.h"
 #include "chrome/common/pref_names.h"
 #include "chrome/test/base/testing_profile.h"
 #include "components/signin/core/browser/signin_manager.h"
+#include "content/public/test/test_browser_thread_bundle.h"
 #include "extensions/browser/event_router.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 
 namespace extensions {
 
 namespace {
 KeyedService* CreateProfileSyncServiceMock(content::BrowserContext* profile) {
   return NULL;
 }
 }  // namespace
 
 // Adds a listener and removes it.
 TEST(SignedInDevicesManager, UpdateListener) {
+  content::TestBrowserThreadBundle thread_bundle;
   scoped_ptr<TestingProfile> profile(new TestingProfile());
   SigninManagerFactory::GetForProfile(profile.get())->
       SetAuthenticatedAccountInfo("gaia_id", "foo");
   ProfileSyncServiceFactory::GetInstance()->SetTestingFactory(
       profile.get(), CreateProfileSyncServiceMock);
   SignedInDevicesManager manager(profile.get());
 
   EventListenerInfo info(api::signed_in_devices::OnDeviceInfoChange::kEventName,
                          "extension1",
                          GURL(),
                          profile.get());
 
   // Add a listener.
   manager.OnListenerAdded(info);
   EXPECT_EQ(manager.change_observers_.size(), 1U);
   EXPECT_EQ(manager.change_observers_[0]->extension_id(), info.extension_id);
 
   // Remove the listener.
   manager.OnListenerRemoved(info);
   EXPECT_TRUE(manager.change_observers_.empty());
 }
 }  // namespace extensions