Pass task runners to AudioManager constructor.

media/audio/audio_manager.h

 // Copyright (c) 2012 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.
 
 #ifndef MEDIA_AUDIO_AUDIO_MANAGER_H_
 #define MEDIA_AUDIO_AUDIO_MANAGER_H_
 
 #include <string>
 
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/strings/string16.h"
 #include "build/build_config.h"
 #include "media/audio/audio_device_name.h"
 #include "media/audio/audio_logging.h"
 #include "media/audio/audio_parameters.h"
 
 namespace base {
 class SingleThreadTaskRunner;
 }
 
 namespace media {
 
 class AudioInputStream;
+class AudioManager;
 class AudioManagerFactory;
 class AudioOutputStream;
 
+class AudioManagerDeleter {
+ public:
+  void operator()(const AudioManager* instance) const;
+};
+using ScopedAudioManagerPtr = scoped_ptr<AudioManager, AudioManagerDeleter>;
+
 // Manages all audio resources.  Provides some convenience functions that avoid
 // the need to provide iterators over the existing streams.
 //
 // Except on OSX, a hang monitor for the audio thread is always created. When a
 // thread hang is detected, it is reported to UMA.  Optionally, if called prior,
 // EnableCrashKeyLoggingForAudioThreadHangs() will cause a non-crash dump to be
 // logged on Windows (this allows us to report driver hangs to Microsoft).
 class MEDIA_EXPORT AudioManager {
  public:
   virtual ~AudioManager();
-
   // This provides an alternative to the statically linked factory method used
   // to create AudioManager. This is useful for dynamically-linked third
   // party clients seeking to provide a platform-specific implementation of
   // AudioManager. After this is called, all static AudioManager::Create*
   // methods will return an instance of AudioManager provided by |factory|. This
   // call may be made at most once per process, and before any calls to static
   // AudioManager::Create* methods. This method takes ownership of |factory|,
   // which must not be NULL.
   static void SetFactory(AudioManagerFactory* factory);
 
-  // Construct the audio manager; only one instance is allowed.  The manager
-  // will forward CreateAudioLog() calls to the provided AudioLogFactory; as
-  // such |audio_log_factory| must outlive the AudioManager.
-  static AudioManager* Create(AudioLogFactory* audio_log_factory);
-
-  // Similar to Create() except also schedules a monitor on the given task
-  // runner to ensure the audio thread is not stuck for more than 60 seconds; if
-  // a hang is detected, the process will be crashed.  See EnableHangMonitor().
-  static AudioManager* CreateWithHangTimer(
-      AudioLogFactory* audio_log_factory,
-      const scoped_refptr<base::SingleThreadTaskRunner>& monitor_task_runner);
-
-  // Similar to Create() except uses a FakeAudioLogFactory for testing.
-  static AudioManager* CreateForTesting();
+  // Construct the audio manager; only one instance is allowed.

[tommi (sloooow) - chröme, 2016/03/19 02:32:41]

since it has come up a few times in the past and been the source of confusion,
can you call out explicitly which one of the below threads will be the UI thread
on Mac?

[alokp, 2016/03/22 21:47:07]

Done.

+  // The returned instance must be deleted on AudioManager::GetTaskRunnner().
+  //
+  // The manager will forward CreateAudioLog() calls to the provided
+  // AudioLogFactory; as such |audio_log_factory| must outlive the AudioManager.
+  //
+  // The manager will use |task_runner| for audio IO. If the given |task_runner|
+  // is NULL, the implementation will choose a default task runner, which can
+  // be obtained by calling GetTaskRunner().
+  //
+  // The manager will use |worker_task_runner| for heavyweight tasks.
+  // The |worker_task_runner| may be the same as |task_runner| or NULL, in
+  // which case the implementation will choose a default one.
+  //
+  // If |monitor_task_runner| is not NULL, a monitor will be scheduled on
+  // |monitor_task_runner| to monitor |task_runner|. See EnableHangMonitor().
+  static ScopedAudioManagerPtr Create(
+      scoped_refptr<base::SingleThreadTaskRunner> task_runner,

[tommi (sloooow) - chröme, 2016/03/19 02:32:41]

nit: passing by value implies that the caller might want to pass ownership. I'm
not sure that's true though since at least some of these task runners are held
elsewhere.

[alokp, 2016/03/22 21:47:07]

I agree. I plan to look into it in a later patch. Please see my response in BML.

+      scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
+      scoped_refptr<base::SingleThreadTaskRunner> monitor_task_runner,
+      AudioLogFactory* audio_log_factory);
 
   // Enables non-crash dumps when audio thread hangs are detected.
   // TODO(dalecurtis): There are no callers to this function at present. A list
   // of bad drivers has been given to Microsoft. This should be re-enabled in
   // the future if Microsoft is able to triage third party drivers.
   // See http://crbug.com/422522
   static void EnableCrashKeyLoggingForAudioThreadHangs();
 
 #if defined(OS_LINUX)
   // Sets the name of the audio source as seen by external apps. Only actually
@@ skipping 98 matching lines @@
   // Returns NULL if the combination of the parameters is not supported, or if
   // we have reached some other platform specific limit.
   //
   // Do not free the returned AudioInputStream. It is owned by AudioManager.
   // When you are done with it, call |Stop()| and |Close()| to release it.
   virtual AudioInputStream* MakeAudioInputStream(
       const AudioParameters& params,
       const std::string& device_id) = 0;
 
   // Returns the task runner used for audio IO.
-  virtual scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() = 0;
+  // TODO(alokp): Rename to task_runner().
+  scoped_refptr<base::SingleThreadTaskRunner> GetTaskRunner() const {
+    return task_runner_;
+  }
 
   // Heavyweight tasks should use GetWorkerTaskRunner() instead of
   // GetTaskRunner(). On most platforms they are the same, but some share the
   // UI loop with the audio IO loop.
-  virtual scoped_refptr<base::SingleThreadTaskRunner> GetWorkerTaskRunner() = 0;
+  // TODO(alokp): Rename to worker_task_runner().
+  scoped_refptr<base::SingleThreadTaskRunner> GetWorkerTaskRunner() const {
+    return worker_task_runner_;
+  }
 
   // Allows clients to listen for device state changes; e.g. preferred sample
   // rate or channel layout changes.  The typical response to receiving this
   // callback is to recreate the stream.
   class AudioDeviceListener {
    public:
     virtual void OnDeviceChange() = 0;
   };
 
   virtual void AddOutputDeviceChangeListener(AudioDeviceListener* listener) = 0;
@@ skipping 26 matching lines @@
   // GetWorkerTaskRunner()).
   virtual std::string GetAssociatedOutputDeviceID(
       const std::string& input_device_id) = 0;
 
   // Create a new AudioLog object for tracking the behavior for one or more
   // instances of the given component.  See AudioLogFactory for more details.
   virtual scoped_ptr<AudioLog> CreateAudioLog(
       AudioLogFactory::AudioComponent component) = 0;
 
  protected:
-  AudioManager();
+  AudioManager(scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+               scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner);
 
  private:
+  scoped_refptr<base::SingleThreadTaskRunner> task_runner_;
+  scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner_;
   DISALLOW_COPY_AND_ASSIGN(AudioManager);
 };
 
 }  // namespace media
 
 #endif  // MEDIA_AUDIO_AUDIO_MANAGER_H_