Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_thread_impl.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 "content/browser/audio_manager_thread.h"
+#include "media/audio/audio_thread_impl.h"
 
 #include "base/threading/thread_task_runner_handle.h"
-#include "build/build_config.h"
 
-namespace content {
+namespace media {
 
-AudioManagerThread::AudioManagerThread() : thread_("AudioThread") {
+AudioThreadImpl::AudioThreadImpl() : thread_("AudioThread") {
 #if defined(OS_WIN)
   thread_.init_com_with_mta(true);
 #endif
   CHECK(thread_.Start());
 
 #if defined(OS_MACOSX)
   // On Mac, the audio task runner must belong to the main thread.
   // See http://crbug.com/158170.
   task_runner_ = base::ThreadTaskRunnerHandle::Get();
 #else
   task_runner_ = thread_.task_runner();
 #endif
+  worker_task_runner_ = thread_.task_runner();
 }
 
-AudioManagerThread::~AudioManagerThread() {}
+AudioThreadImpl::~AudioThreadImpl() {}

[o1ka, 2017/05/10 15:57:57]

DCHECK that it's called on |task_runner_| on Mac?
And add a comment that on Mac we can still have tasks posted on on
|task_runner_|  after Stop() (since it's the main thread task runner and we
don't stop the main thread) - but it's fine since AudioThreadImpl destructor
will be called on the main thread during main message loop shutdown?

[alokp, 2017/05/10 18:04:03]

I do not think we want to verify anything special for mac. This class must be
created and destroyed on the same thread on all platforms. I added thread
checker to validate that. This also validates what you wanted to validate on
mac.

Added comments about mac-specific issues in Stop.

 
-}  // namespace content
+void AudioThreadImpl::Stop() {
+  thread_.Stop();
+}
+
+base::SingleThreadTaskRunner* AudioThreadImpl::GetTaskRunner() {
+  return task_runner_.get();
+}
+
+base::SingleThreadTaskRunner* AudioThreadImpl::GetWorkerTaskRunner() {
+  return worker_task_runner_.get();
+}
+
+}  // namespace media