Use ScopedTaskEnvironment instead of MessageLoop in chrome unit tests.

chrome/browser/signin/mutable_profile_oauth2_token_service_delegate_unittest.cc

 // 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.
 
 #include "chrome/browser/signin/mutable_profile_oauth2_token_service_delegate.h"
 
 #include <map>
 #include <string>
 #include <utility>
 #include <vector>
 
 #include "base/command_line.h"
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "build/build_config.h"
 #include "components/os_crypt/os_crypt_mocker.h"
 #include "components/prefs/pref_registry_simple.h"
 #include "components/prefs/scoped_user_pref_update.h"
 #include "components/prefs/testing_pref_service.h"
 #include "components/signin/core/browser/profile_oauth2_token_service.h"
 #include "components/signin/core/browser/signin_error_controller.h"
 #include "components/signin/core/browser/test_signin_client.h"
 #include "components/signin/core/browser/webdata/token_web_data.h"
@@ skipping 119 matching lines @@
   }
 
   void ExpectOneTokensLoadedNotification() {
     EXPECT_EQ(0, token_available_count_);
     EXPECT_EQ(0, token_revoked_count_);
     EXPECT_EQ(1, tokens_loaded_count_);
     ResetObserverCounts();
   }
 
  protected:
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   net::FakeURLFetcherFactory factory_;
   std::unique_ptr<TestSigninClient> client_;
   std::unique_ptr<MutableProfileOAuth2TokenServiceDelegate>
       oauth2_service_delegate_;
   TestingOAuth2TokenServiceConsumer consumer_;
   SigninErrorController signin_error_controller_;
   TestingPrefServiceSimple pref_service_;
   AccountTrackerService account_tracker_service_;
   int access_token_success_count_;
   int access_token_failure_count_;
@@ skipping 546 matching lines @@
   EXPECT_EQ(1, tokens_loaded_count_);
   EXPECT_EQ(2, token_available_count_);
   EXPECT_EQ(0, token_revoked_count_);
   EXPECT_EQ(1, start_batch_changes_);
   EXPECT_EQ(1, end_batch_changes_);
   EXPECT_TRUE(
       oauth2_service_delegate_->RefreshTokenIsAvailable(primary_account));
   EXPECT_TRUE(
       oauth2_service_delegate_->RefreshTokenIsAvailable(secondary_account));
 }