Pass task runners to AudioManager constructor.

media/audio/pulse/audio_manager_pulse.cc

Index: media/audio/pulse/audio_manager_pulse.cc
diff --git a/media/audio/pulse/audio_manager_pulse.cc b/media/audio/pulse/audio_manager_pulse.cc
index d6e9543183a0f86c8130b1459f8cd6a65e54ef2d..e9e27707a8c17848742d9492258942d12c7879c7 100644
--- a/media/audio/pulse/audio_manager_pulse.cc
+++ b/media/audio/pulse/audio_manager_pulse.cc
@@ -47,18 +47,97 @@ static const base::FilePath::CharType kPulseLib[] =
     FILE_PATH_LITERAL("libpulse.so.0");
 #endif
 
-// static
-AudioManager* AudioManagerPulse::Create(AudioLogFactory* audio_log_factory) {
-  scoped_ptr<AudioManagerPulse> ret(new AudioManagerPulse(audio_log_factory));
-  if (ret->Init())
-    return ret.release();
-
-  DVLOG(1) << "PulseAudio is not available on the OS";
-  return NULL;
+namespace {
+void DestroyPulse(pa_threaded_mainloop* input_mainloop,
+                  pa_context* input_context) {
+  DCHECK(input_mainloop);
+
+  {
+    AutoPulseLock auto_lock(input_mainloop);
+    if (input_context) {
+      // Clear our state callback.
+      pa_context_set_state_callback(input_context, NULL, NULL);
+      pa_context_disconnect(input_context);
+      pa_context_unref(input_context);
+    }
+  }
+
+  pa_threaded_mainloop_stop(input_mainloop);
+  pa_threaded_mainloop_free(input_mainloop);
 }
 
-AudioManagerPulse::AudioManagerPulse(AudioLogFactory* audio_log_factory)
-    : AudioManagerBase(audio_log_factory),
+bool InitPulse(pa_threaded_mainloop** input_mainloop,
+               pa_context** input_context) {
+#if defined(DLOPEN_PULSEAUDIO)
+  StubPathMap paths;
+
+  // Check if the pulse library is avialbale.
+  paths[kModulePulse].push_back(kPulseLib);
+  if (!InitializeStubs(paths)) {
+    VLOG(1) << "Failed on loading the Pulse library and symbols";
+    return false;
+  }
+#endif  // defined(DLOPEN_PULSEAUDIO)
+
+  // Create a mainloop API and connect to the default server.
+  // The mainloop is the internal asynchronous API event loop.
+  pa_threaded_mainloop* mainloop = pa_threaded_mainloop_new();
+  if (!mainloop)
+    return false;
+
+  // Start the threaded mainloop.
+  if (pa_threaded_mainloop_start(mainloop)) {
+    DestroyPulse(mainloop, nullptr);
+    return false;
+  }
+
+  // Lock the event loop object, effectively blocking the event loop thread
+  // from processing events. This is necessary.
+  AutoPulseLock auto_lock(mainloop);
+
+  pa_mainloop_api* mainloop_api = pa_threaded_mainloop_get_api(mainloop);
+  pa_context* context = pa_context_new(mainloop_api, "Chrome input");
+  if (!context) {
+    DestroyPulse(mainloop, nullptr);
+    return false;
+  }
+
+  pa_context_set_state_callback(context, &pulse::ContextStateCallback,
+                                mainloop);
+  if (pa_context_connect(context, NULL, PA_CONTEXT_NOAUTOSPAWN, NULL)) {
+    VLOG(1) << "Failed to connect to the context.  Error: "
+            << pa_strerror(pa_context_errno(context));
+    DestroyPulse(mainloop, context);
+    return false;
+  }
+
+  // Wait until |input_context_| is ready.  pa_threaded_mainloop_wait() must be
+  // called after pa_context_get_state() in case the context is already ready,
+  // otherwise pa_threaded_mainloop_wait() will hang indefinitely.
+  while (true) {
+    pa_context_state_t context_state = pa_context_get_state(context);
+    if (!PA_CONTEXT_IS_GOOD(context_state)) {
+      DestroyPulse(mainloop, context);
+      return false;
+    }
+    if (context_state == PA_CONTEXT_READY)
+      break;
+    pa_threaded_mainloop_wait(mainloop);
+  }
+
+  *input_mainloop = mainloop;
+  *input_context = context;
+  return true;
+}
+}  // namespace
+
+AudioManagerPulse::AudioManagerPulse(
+    scoped_refptr<base::SingleThreadTaskRunner> task_runner,
+    scoped_refptr<base::SingleThreadTaskRunner> worker_task_runner,
+    AudioLogFactory* audio_log_factory)
+    : AudioManagerBase(std::move(task_runner),
+                       std::move(worker_task_runner),
+                       audio_log_factory),
       input_mainloop_(NULL),
       input_context_(NULL),
       devices_(NULL),
@@ -67,11 +146,24 @@ AudioManagerPulse::AudioManagerPulse(AudioLogFactory* audio_log_factory)
 }
 
 AudioManagerPulse::~AudioManagerPulse() {
-  Shutdown();
+  DCHECK(GetTaskRunner()->BelongsToCurrentThread());
+  // Do not destroy pulse here since AudioManagerBase destructor needs it.
+  if (input_mainloop_) {
+    GetTaskRunner()->PostTask(
+        FROM_HERE, base::Bind(&DestroyPulse, input_mainloop_, input_context_));
+  } else {
+    DCHECK(!input_context_);
+  }
+}
 
-  // The Pulse objects are the last things to be destroyed since Shutdown()
-  // needs them.
-  DestroyPulse();
+bool AudioManagerPulse::Init() {
+  DCHECK(!input_mainloop_);
+  // TODO(alokp): Investigate if InitPulse can happen on the audio thread.
+  // It currently needs to happen on the main thread so that is InitPulse fails,
+  // we can fallback to ALSA implementation. Initializing it on audio thread
+  // would unblock the main thread and make InitPulse consistent with
+  // DestroyPulse which happens on the audio thread.
+  return InitPulse(&input_mainloop_, &input_context_);
 }
 
 // Implementation of AudioManager.
@@ -217,85 +309,6 @@ int AudioManagerPulse::GetNativeSampleRate() {
   return native_input_sample_rate_;
 }
 
-bool AudioManagerPulse::Init() {
-  DCHECK(!input_mainloop_);
-
-#if defined(DLOPEN_PULSEAUDIO)
-  StubPathMap paths;
-
-  // Check if the pulse library is avialbale.
-  paths[kModulePulse].push_back(kPulseLib);
-  if (!InitializeStubs(paths)) {
-    VLOG(1) << "Failed on loading the Pulse library and symbols";
-    return false;
-  }
-#endif  // defined(DLOPEN_PULSEAUDIO)
-
-  // Create a mainloop API and connect to the default server.
-  // The mainloop is the internal asynchronous API event loop.
-  input_mainloop_ = pa_threaded_mainloop_new();
-  if (!input_mainloop_)
-    return false;
-
-  // Start the threaded mainloop.
-  if (pa_threaded_mainloop_start(input_mainloop_))
-    return false;
-
-  // Lock the event loop object, effectively blocking the event loop thread
-  // from processing events. This is necessary.
-  AutoPulseLock auto_lock(input_mainloop_);
-
-  pa_mainloop_api* pa_mainloop_api =
-      pa_threaded_mainloop_get_api(input_mainloop_);
-  input_context_ = pa_context_new(pa_mainloop_api, "Chrome input");
-  if (!input_context_)
-    return false;
-
-  pa_context_set_state_callback(input_context_, &pulse::ContextStateCallback,
-                                input_mainloop_);
-  if (pa_context_connect(input_context_, NULL, PA_CONTEXT_NOAUTOSPAWN, NULL)) {
-    VLOG(1) << "Failed to connect to the context.  Error: "
-            << pa_strerror(pa_context_errno(input_context_));
-    return false;
-  }
-
-  // Wait until |input_context_| is ready.  pa_threaded_mainloop_wait() must be
-  // called after pa_context_get_state() in case the context is already ready,
-  // otherwise pa_threaded_mainloop_wait() will hang indefinitely.
-  while (true) {
-    pa_context_state_t context_state = pa_context_get_state(input_context_);
-    if (!PA_CONTEXT_IS_GOOD(context_state))
-      return false;
-    if (context_state == PA_CONTEXT_READY)
-      break;
-    pa_threaded_mainloop_wait(input_mainloop_);
-  }
-
-  return true;
-}
-
-void AudioManagerPulse::DestroyPulse() {
-  if (!input_mainloop_) {
-    DCHECK(!input_context_);
-    return;
-  }
-
-  {
-    AutoPulseLock auto_lock(input_mainloop_);
-    if (input_context_) {
-      // Clear our state callback.
-      pa_context_set_state_callback(input_context_, NULL, NULL);
-      pa_context_disconnect(input_context_);
-      pa_context_unref(input_context_);
-      input_context_ = NULL;
-    }
-  }
-
-  pa_threaded_mainloop_stop(input_mainloop_);
-  pa_threaded_mainloop_free(input_mainloop_);
-  input_mainloop_ = NULL;
-}
-
 void AudioManagerPulse::InputDevicesInfoCallback(pa_context* context,
                                                  const pa_source_info* info,
                                                  int error, void *user_data) {