Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/audio_thread_impl.cc

Index: media/audio/audio_thread_impl.cc
diff --git a/media/audio/audio_thread_impl.cc b/media/audio/audio_thread_impl.cc
new file mode 100644
index 0000000000000000000000000000000000000000..f7c52863279237966b7998c025939bedd588039b
--- /dev/null
+++ b/media/audio/audio_thread_impl.cc
@@ -0,0 +1,48 @@
+// 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 "media/audio/audio_thread_impl.h"
+
+#include "base/threading/thread_task_runner_handle.h"
+
+namespace media {
+
+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();
+}
+
+AudioThreadImpl::~AudioThreadImpl() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+}
+
+void AudioThreadImpl::Stop() {
+  DCHECK_CALLED_ON_VALID_THREAD(thread_checker_);
+
+  // Note that on MACOSX, we can still have tasks posted on the |task_runner_|,
+  // since it is the main thread task runner and we do not stop the main thread.
+  // But this is fine becuase none of those tasks will actually run.
+  thread_.Stop();
+}
+
+base::SingleThreadTaskRunner* AudioThreadImpl::GetTaskRunner() {
+  return task_runner_.get();
+}
+
+base::SingleThreadTaskRunner* AudioThreadImpl::GetWorkerTaskRunner() {
+  return worker_task_runner_.get();
+}
+
+}  // namespace media