Pass task runners to AudioManager constructor.

content/browser/browser_main_loop.cc

Index: content/browser/browser_main_loop.cc
diff --git a/content/browser/browser_main_loop.cc b/content/browser/browser_main_loop.cc
index 91fec92c1f173700098640a212dfd70ec612aaa5..4bc9a4a590db07983c8d78739374c62cc01e55f5 100644
--- a/content/browser/browser_main_loop.cc
+++ b/content/browser/browser_main_loop.cc
@@ -73,7 +73,6 @@
 #include "content/public/common/result_codes.h"
 #include "device/battery/battery_status_service.h"
 #include "ipc/mojo/scoped_ipc_support.h"
-#include "media/audio/audio_manager.h"
 #include "media/base/media.h"
 #include "media/base/user_input_monitor.h"
 #include "media/midi/midi_manager.h"
@@ -1256,8 +1255,24 @@ int BrowserMainLoop::BrowserThreadsStarted() {
 
   {
     TRACE_EVENT0("startup", "BrowserThreadsStarted::Subsystem:AudioMan");
-    audio_manager_.reset(media::AudioManager::CreateWithHangTimer(
-        MediaInternals::GetInstance(), io_thread_->task_runner()));
+    scoped_refptr<base::SingleThreadTaskRunner> audio_task_runner;
+    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner;
+    scoped_refptr<base::SingleThreadTaskRunner> monitor_task_runner;
+    media::AudioLogFactory* audio_log_factory = MediaInternals::GetInstance();
+#if defined(OS_MACOSX)
+    // CoreAudio calls must occur on the main thread of the process, which in
+    // our case is sadly the browser UI thread. Failure to execute calls on the
+    // right thread leads to crashes and odd behavior.
+    // See http://crbug.com/158170.
+    // Since the audio thread is the UI thread, a hang monitor is not
+    // necessary or recommended.
+    audio_task_runner = base::ThreadTaskRunnerHandle::Get();
+#else
+    monitor_task_runner = io_thread_->task_runner();
+#endif
+    audio_manager_ =
+        media::AudioManager::Create(audio_task_runner, worker_task_runner,

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

nit: since these are going out of scope and Create() accepts reptrs by value,
you should use std::move().  Alternatively, if ownership passing is not
intended, change the Create() signature to accept by const&.

[alokp, 2016/03/22 21:47:06]

I think we need to pass the ownership to match the signature of
AudioManager::GetTaskRunner(). I have a TODO to rename it to
AudioManager::task_runner(). At that time I will evaluate the various callsites
and if none of them assume ownership, I will convert it to const reference
everywhere. Although to be honest I really do not understand the rationale
behind passing a const reference. Shouldn't we pass raw pointers instead when
ownership is not being transferred?

I have used std::move here for now.

+                                    monitor_task_runner, audio_log_factory);
   }
 
   {