Use ScopedTaskEnvironment instead of MessageLoop in components unit tests.

components/captive_portal/captive_portal_detector_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 "components/captive_portal/captive_portal_detector.h"
 
 #include <memory>
 
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "base/time/time.h"
 #include "components/captive_portal/captive_portal_testing_utils.h"
 #include "net/base/net_errors.h"
 #include "net/url_request/url_request_test_util.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "url/gurl.h"
 
 namespace captive_portal {
 
@@ skipping 83 matching lines @@
     ASSERT_TRUE(FetchingURL());
     base::RunLoop().RunUntilIdle();
 
     detector()->Cancel();
 
     ASSERT_FALSE(FetchingURL());
     EXPECT_EQ(0, client.num_results_received());
   }
 
  private:
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<CaptivePortalDetector> detector_;
 };
 
 // Test that the CaptivePortalDetector returns the expected result
 // codes in response to a variety of probe results.
 TEST_F(CaptivePortalDetectorTest, CaptivePortalResultCodes) {
   CaptivePortalDetector::Results results;
   results.result = captive_portal::RESULT_INTERNET_CONNECTED;
   results.response_code = 204;
 
@@ skipping 76 matching lines @@
 
 TEST_F(CaptivePortalDetectorTest, Cancel) {
   RunCancelTest();
   CaptivePortalDetector::Results results;
   results.result = captive_portal::RESULT_INTERNET_CONNECTED;
   results.response_code = 204;
   RunTest(results, net::OK, 204, NULL);
 }
 
 }  // namespace captive_portal