Use ScopedTaskEnvironment instead of MessageLoop in chrome unit tests.

chrome/browser/printing/cloud_print/privet_notifications_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 "chrome/browser/printing/cloud_print/privet_notifications.h"
 
 #include <memory>
 
 #include "base/memory/ptr_util.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "chrome/browser/notifications/notification_test_util.h"
 #include "chrome/browser/printing/cloud_print/privet_http_asynchronous_factory.h"
 #include "chrome/browser/printing/cloud_print/privet_http_impl.h"
 #include "chrome/test/base/testing_browser_process.h"
 #include "chrome/test/base/testing_profile.h"
 #include "chrome/test/base/testing_profile_manager.h"
 #include "content/public/test/test_browser_thread_bundle.h"
 #include "net/url_request/test_url_fetcher_factory.h"
 #include "net/url_request/url_request_test_util.h"
@@ skipping 90 matching lines @@
     fetcher->set_status(
         net::URLRequestStatus(net::URLRequestStatus::SUCCESS, net::OK));
     fetcher->set_response_code(200);
     fetcher->delegate()->OnURLFetchComplete(fetcher);
     return true;
   }
 
  protected:
   StrictMock<MockPrivetNotificationsListenerDeleagate> mock_delegate_;
   std::unique_ptr<PrivetNotificationsListener> notification_listener_;
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   scoped_refptr<net::TestURLRequestContextGetter> request_context_;
   net::TestURLFetcherFactory fetcher_factory_;
   DeviceDescription description_;
 };
 
 TEST_F(PrivetNotificationsListenerTest, DisappearReappearTest) {
   EXPECT_CALL(mock_delegate_, PrivetNotify(1, true));
   notification_listener_->DeviceChanged(kExampleDeviceName, description_);
   EXPECT_TRUE(SuccessfulResponseToInfo(kInfoResponseUptime20));
 
@@ skipping 179 matching lines @@
 
   EXPECT_EQ("", service.open_tab_url().spec());
   EXPECT_EQ(0U, service.open_tab_count());
   EXPECT_EQ(1U, service.disable_notifications_count());
   EXPECT_EQ(0U, ui_manager()->GetNotificationCount());
 }
 
 }  // namespace
 
 }  // namespace cloud_print