Ensures that audio tasks cannot run after AudioManager is deleted.

media/audio/linux/audio_manager_linux.cc

Index: media/audio/linux/audio_manager_linux.cc
diff --git a/media/audio/linux/audio_manager_linux.cc b/media/audio/linux/audio_manager_linux.cc
index 374d2ab84dcbfaaa4aaf0969c4f7f3f1b7d14ca9..c5111e1e9c2b487c6b3fa812ee9b40375a81547a 100644
--- a/media/audio/linux/audio_manager_linux.cc
+++ b/media/audio/linux/audio_manager_linux.cc
@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 #include "base/command_line.h"
+#include "base/memory/ptr_util.h"
 #include "base/metrics/histogram_macros.h"
 #include "media/base/media_switches.h"
 
@@ -27,16 +28,14 @@ enum LinuxAudioIO {
   kAudioIOMax = kCras  // Must always be equal to largest logged entry.
 };
 
-ScopedAudioManagerPtr CreateAudioManager(
-    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
-    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
+std::unique_ptr<media::AudioManager> CreateAudioManager(
+    std::unique_ptr<AudioThread> audio_thread,
     AudioLogFactory* audio_log_factory) {
 #if defined(USE_CRAS)
   if (base::CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseCras)) {
     UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kCras, kAudioIOMax + 1);
-    return ScopedAudioManagerPtr(
-        new AudioManagerCras(std::move(task_runner),
-                             std::move(worker_task_runner), audio_log_factory));
+    return base::MakeUnique<AudioManagerCras>(std::move(audio_thread),
+                                              audio_log_factory);
   }
 #endif
 
@@ -44,25 +43,23 @@ ScopedAudioManagerPtr CreateAudioManager(
   // Do not move task runners when creating AudioManagerPulse.
   // If the creation fails, we need to use the task runners to create other
   // AudioManager implementations.
-  std::unique_ptr<AudioManagerPulse, AudioManagerDeleter> manager(
-      new AudioManagerPulse(task_runner, worker_task_runner,
-                            audio_log_factory));
+  // TODO(alokp): Fix fallback to alsa/fake path.
+  auto manager = base::MakeUnique<AudioManagerPulse>(std::move(audio_thread),

[alokp, 2017/04/26 20:55:00]

Dale: Is there an alternate way to check if pulseaudio is supported? If I need
to support this fallback to Alsa, we would need to pass |audio_thread| as raw
pointer. Any suggestions?

[DaleCurtis, 2017/04/26 20:56:35]

No, but there's no reason we can't extract Init() to some static function and
use that without passing the AM thread in.

[alokp, 2017/04/26 21:02:50]

Are you suggesting that the static Init return pa_threaded_mainloop and
pa_context that gets fed into AudioManagerPulse constructor? That would work.

[DaleCurtis, 2017/04/26 21:07:09]

Yup.

+                                                     audio_log_factory);
   if (manager->Init()) {
     UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kPulse, kAudioIOMax + 1);
-    return std::move(manager);
+    return manager;
   }
   DVLOG(1) << "PulseAudio is not available on the OS";
 #endif
 
 #if defined(USE_ALSA)
   UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kAlsa, kAudioIOMax + 1);
-  return ScopedAudioManagerPtr(
-      new AudioManagerAlsa(std::move(task_runner),
-                           std::move(worker_task_runner), audio_log_factory));
+  return base::MakeUnique<AudioManagerAlsa>(std::move(audio_thread),
+                                            audio_log_factory);
 #else
-  return ScopedAudioManagerPtr(
-      new FakeAudioManager(std::move(task_runner),
-                           std::move(worker_task_runner), audio_log_factory));
+  return base::MakeUnique<FakeAudioManager>(std::move(audio_thread),
+                                            audio_log_factory);
 #endif
 }