Pass task runners to AudioManager constructor.

content/browser/browser_main_loop.cc

 // 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.
 
 #include "content/browser/browser_main_loop.h"
 
 #include <stddef.h>
 #include <utility>
 
 #include "base/bind.h"
@@ skipping 55 matching lines @@
 #include "content/common/mojo/mojo_shell_connection_impl.h"
 #include "content/public/browser/browser_main_parts.h"
 #include "content/public/browser/content_browser_client.h"
 #include "content/public/browser/render_process_host.h"
 #include "content/public/browser/tracing_controller.h"
 #include "content/public/common/content_switches.h"
 #include "content/public/common/main_function_params.h"
 #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"
 #include "mojo/edk/embedder/embedder.h"
 #include "mojo/shell/public/cpp/shell.h"
 #include "net/base/network_change_notifier.h"
 #include "net/socket/client_socket_factory.h"
 #include "net/ssl/ssl_config_service.h"
 #include "skia/ext/event_tracer_impl.h"
 #include "skia/ext/skia_memory_dump_provider.h"
@@ skipping 1162 matching lines @@
       BrowserGpuMemoryBufferManager::current(), "BrowserGpuMemoryBufferManager",
       io_thread_->task_runner());
 #if defined(OS_ANDROID)
   base::trace_event::MemoryDumpManager::GetInstance()->RegisterDumpProvider(
       tracing::GraphicsMemoryDumpProvider::GetInstance(), "AndroidGraphics",
       nullptr);
 #endif
 
   {
     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);
   }
 
   {
     TRACE_EVENT0("startup", "BrowserThreadsStarted::Subsystem:MidiManager");
     midi_manager_.reset(media::midi::MidiManager::Create());
   }
 
 #if defined(OS_WIN)
   system_message_window_.reset(new media::SystemMessageWindowWin);
 #elif defined(OS_LINUX) && defined(USE_UDEV)
@@ skipping 210 matching lines @@
   DCHECK(is_tracing_startup_for_duration_);
 
   is_tracing_startup_for_duration_ = false;
   TracingController::GetInstance()->StopTracing(
       TracingController::CreateFileSink(
           startup_trace_file_,
           base::Bind(OnStoppedStartupTracing, startup_trace_file_)));
 }
 
 }  // namespace content