Use ScopedTaskEnvironment instead of MessageLoop in media unit tests.

media/remoting/courier_renderer_unittest.cc

 // Copyright 2016 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 "media/remoting/courier_renderer.h"
 
 #include "base/memory/ptr_util.h"
 #include "base/run_loop.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/test/simple_test_tick_clock.h"
 #include "base/threading/thread_task_runner_handle.h"
 #include "media/base/pipeline_status.h"
 #include "media/base/renderer_client.h"
 #include "media/base/test_helpers.h"
 #include "media/remoting/fake_media_resource.h"
 #include "media/remoting/fake_remoter.h"
 #include "media/remoting/renderer_controller.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ skipping 302 matching lines @@
     message->set_audio_bytes_decoded(stats.audio_bytes_decoded);
     message->set_video_bytes_decoded(stats.video_bytes_decoded);
     message->set_video_frames_decoded(stats.video_frames_decoded);
     message->set_video_frames_dropped(stats.video_frames_dropped);
     message->set_audio_memory_usage(stats.audio_memory_usage);
     message->set_video_memory_usage(stats.video_memory_usage);
     OnReceivedRpc(std::move(rpc));
     RunPendingTasks();
   }
 
-  base::MessageLoop message_loop_;
+  base::test::ScopedTaskEnvironment scoped_task_environment_;
   std::unique_ptr<RendererController> controller_;
   std::unique_ptr<RendererClientImpl> render_client_;
   std::unique_ptr<FakeMediaResource> media_resource_;
   std::unique_ptr<CourierRenderer> renderer_;
   base::SimpleTestTickClock* clock_;  // Owned by |renderer_|;
 
   // RPC handles.
   const int receiver_renderer_handle_;
   const int receiver_audio_demuxer_callback_handle_;
   const int receiver_video_demuxer_callback_handle_;
@@ skipping 299 matching lines @@
     ASSERT_FALSE(DidEncounterFatalError());  // Not enough measurements.
     IssueStatisticsUpdateRpc();
     clock_->Advance(base::TimeDelta::FromSeconds(1));
     RunPendingTasks();
   }
   ASSERT_TRUE(DidEncounterFatalError());
 }
 
 }  // namespace remoting
 }  // namespace media