Reland: Pass task runners to AudioManager constructor.

content/browser/renderer_host/media/audio_output_device_enumerator.cc

 // Copyright (c) 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/browser/renderer_host/media/audio_output_device_enumerator.h"
 
 #include "base/callback_helpers.h"
 #include "base/location.h"
 #include "base/single_thread_task_runner.h"
 #include "base/task_runner_util.h"
@@ skipping 99 matching lines @@
 bool AudioOutputDeviceEnumerator::IsCacheEnabled() {
   DCHECK(thread_checker_.CalledOnValidThread());
   return cache_policy_ != CACHE_POLICY_NO_CACHING;
 }
 
 void AudioOutputDeviceEnumerator::DoEnumerateDevices() {
   DCHECK(thread_checker_.CalledOnValidThread());
   is_enumeration_ongoing_ = true;
   seq_last_enumeration_ = NewEventSequence();
   base::PostTaskAndReplyWithResult(
-      audio_manager_->GetTaskRunner().get(), FROM_HERE,
+      audio_manager_->GetTaskRunner(), FROM_HERE,
       base::Bind(&EnumerateDevicesOnDeviceThread, audio_manager_),
       base::Bind(&AudioOutputDeviceEnumerator::DevicesEnumerated,
                  weak_factory_.GetWeakPtr()));
 }
 
 void AudioOutputDeviceEnumerator::DevicesEnumerated(
     const AudioOutputDeviceEnumeration& snapshot) {
   DCHECK(thread_checker_.CalledOnValidThread());
   is_enumeration_ongoing_ = false;
   if (IsLastEnumerationValid()) {
@@ skipping 15 matching lines @@
   return ++current_event_sequence_;
 }
 
 bool AudioOutputDeviceEnumerator::IsLastEnumerationValid() const {
   DCHECK(thread_checker_.CalledOnValidThread());
   return seq_last_enumeration_ > seq_last_invalidation_ &&
          !is_enumeration_ongoing_;
 }
 
 }  // namespace content