Use ScopedTaskEnvironment instead of MessageLoop in content unit tests.

content/renderer/media_recorder/audio_track_recorder_unittest.cc

 // Copyright 2015 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 "content/renderer/media_recorder/audio_track_recorder.h"
 
 #include <stdint.h>
 
 #include <string>
 
 #include "base/bind.h"
 #include "base/bind_helpers.h"
 #include "base/macros.h"
 #include "base/run_loop.h"
 #include "base/stl_util.h"
+#include "base/test/scoped_task_environment.h"
 #include "base/time/time.h"
 #include "content/renderer/media/media_stream_audio_source.h"
 #include "media/audio/simple_sources.h"
 #include "testing/gmock/include/gmock/gmock.h"
 #include "testing/gtest/include/gtest/gtest.h"
 #include "third_party/WebKit/public/platform/WebString.h"
 #include "third_party/WebKit/public/web/WebHeap.h"
 #include "third_party/opus/src/include/opus.h"
 
 using ::testing::_;
@@ skipping 158 matching lines @@
     // per buffer.
     EXPECT_EQ(kDefaultSampleRate * kOpusBufferDurationMs / 1000,
               opus_decode_float(
                   opus_decoder_, reinterpret_cast<uint8_t*>(
                                      base::string_as_array(encoded_data.get())),
                   encoded_data->size(), buffer_.get(), kFramesPerBuffer, 0));
 
     DoOnEncodedAudio(params, *encoded_data, timestamp);
   }
 
-  const base::MessageLoop message_loop_;
+  const base::test::ScopedTaskEnvironment scoped_task_environment_;
 
   // ATR and WebMediaStreamTrack for fooling it.
   std::unique_ptr<AudioTrackRecorder> audio_track_recorder_;
   blink::WebMediaStreamTrack blink_track_;
 
   // Two different sets of AudioParameters for testing re-init of ATR.
   const media::AudioParameters first_params_;
   const media::AudioParameters second_params_;
 
   // AudioSources for creating AudioBuses.
@@ skipping 92 matching lines @@
 
   if (GetParam().sample_rate % 100)
     audio_track_recorder_->OnData(*GetFirstSourceAudioBus(), TimeTicks::Now());
 
   run_loop.Run();
   Mock::VerifyAndClearExpectations(this);
 }
 
 INSTANTIATE_TEST_CASE_P(, AudioTrackRecorderTest, ValuesIn(kATRTestParams));
 }  // namespace content