Data race fix: Replace use of MessageLoop raw pointer in MSAudioProcessor.

content/renderer/media/webrtc/processed_local_audio_source_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 <memory>
 #include <string>
 
 #include "base/logging.h"
+#include "base/message_loop/message_loop.h"
 #include "build/build_config.h"
 #include "content/public/renderer/media_stream_audio_sink.h"
 #include "content/renderer/media/media_stream_audio_track.h"
 #include "content/renderer/media/mock_audio_device_factory.h"
 #include "content/renderer/media/mock_constraint_factory.h"
 #include "content/renderer/media/webrtc/mock_peer_connection_dependency_factory.h"
 #include "content/renderer/media/webrtc/processed_local_audio_source.h"
 #include "media/base/audio_bus.h"
 #include "media/base/audio_parameters.h"
 #include "testing/gmock/include/gmock/gmock.h"
@@ skipping 111 matching lines @@
 
   MediaStreamAudioSource* audio_source() const {
     return MediaStreamAudioSource::From(blink_audio_source_);
   }
 
   const blink::WebMediaStreamTrack& blink_audio_track() {
     return blink_audio_track_;
   }
 
  private:
+  base::MessageLoop main_thread_message_loop_;  // Needed for MSAudioProcessor.
   MockAudioDeviceFactory mock_audio_device_factory_;
   MockPeerConnectionDependencyFactory mock_dependency_factory_;
   blink::WebMediaStreamSource blink_audio_source_;
   blink::WebMediaStreamTrack blink_audio_track_;
 };
 
 // Tests a basic end-to-end start-up, track+sink connections, audio flow, and
 // shut-down. The unit tests in media_stream_audio_unittest.cc provide more
 // comprehensive testing of the object graph connections and multi-threading
 // concerns.
@@ skipping 70 matching lines @@
   // Even though ConnectToTrack() failed, there should still have been a new
   // MediaStreamAudioTrack instance created, owned by the
   // blink::WebMediaStreamTrack.
   EXPECT_TRUE(MediaStreamAudioTrack::From(blink_audio_track()));
 }
 
 // TODO(miu): There's a lot of logic in ProcessedLocalAudioSource around
 // constraints processing and validation that should have unit testing.
 
 }  // namespace content