Revert of Pass task runners to AudioManager constructor.

components/audio_modem/audio_recorder_impl.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 "components/audio_modem/audio_recorder_impl.h"
 
 #include <algorithm>
 #include <utility>
 #include <vector>
 
@@ skipping 180 matching lines @@
 }
 
 void AudioRecorderImpl::OnError(media::AudioInputStream* /* stream */) {
   LOG(ERROR) << "Error during sound recording.";
   media::AudioManager::Get()->GetTaskRunner()->PostTask(
       FROM_HERE,
       base::Bind(&AudioRecorderImpl::StopAndCloseOnAudioThread,
                  base::Unretained(this)));
 }
 
+void AudioRecorderImpl::FlushAudioLoopForTesting() {
+  if (media::AudioManager::Get()->GetTaskRunner()->BelongsToCurrentThread())
+    return;
+
+  // Queue task on the audio thread, when it is executed, that means we've
+  // successfully executed all the tasks before us.
+  base::RunLoop rl;
+  media::AudioManager::Get()->GetTaskRunner()->PostTaskAndReply(
+      FROM_HERE,
+      base::Bind(
+          base::IgnoreResult(&AudioRecorderImpl::FlushAudioLoopForTesting),
+          base::Unretained(this)),
+      rl.QuitClosure());
+  rl.Run();
+}
+
 }  // namespace audio_modem